diff --git a/Consistence/Sniffs/Exceptions/ExceptionDeclarationSniff.php b/Consistence/Sniffs/Exceptions/ExceptionDeclarationSniff.php
new file mode 100644
index 0000000..68bc087
--- /dev/null
+++ b/Consistence/Sniffs/Exceptions/ExceptionDeclarationSniff.php
@@ -0,0 +1,143 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+use PHP_CodeSniffer\Files\File as PhpCsFile;
+use SlevomatCodingStandard\Helpers\ClassHelper;
+use SlevomatCodingStandard\Helpers\FunctionHelper;
+use SlevomatCodingStandard\Helpers\StringHelper;
+use SlevomatCodingStandard\Helpers\TokenHelper;
+
+class ExceptionDeclarationSniff implements \PHP_CodeSniffer\Sniffs\Sniff
+{
+
+	const CODE_NOT_ENDING_WITH_EXCEPTION = 'NotEndingWithException';
+	const CODE_NOT_CHAINABLE = 'NotChainable';
+	const CODE_INCORRECT_EXCEPTION_DIRECTORY = 'IncorrectExceptionDirectory';
+
+	/** @var string */
+	public $exceptionsDirectoryName = 'exceptions';
+
+	/**
+	 * @return int[]
+	 */
+	public function register(): array
+	{
+		return [
+			T_CLASS,
+			T_INTERFACE,
+		];
+	}
+
+	/**
+	 * @param \PHP_CodeSniffer\Files\File $phpcsFile
+	 * @param int $classPointer
+	 */
+	public function process(PhpCsFile $phpcsFile, $classPointer)
+	{
+		$extendedClassName = $phpcsFile->findExtendedClassName($classPointer);
+		if ($extendedClassName === false) {
+			return; //does not extend anything
+		}
+
+		if (!StringHelper::endsWith($extendedClassName, 'Exception')) {
+			return; // does not extend Exception, is not an exception
+		}
+
+		$this->checkExceptionName($phpcsFile, $classPointer);
+
+		$this->checkExceptionDirectoryName($phpcsFile, $classPointer);
+
+		$this->checkThatExceptionIsChainable($phpcsFile, $classPointer);
+	}
+
+	private function checkExceptionName(PhpCsFile $phpcsFile, int $classPointer)
+	{
+		$className = ClassHelper::getName($phpcsFile, $classPointer);
+		if (!StringHelper::endsWith($className, 'Exception')) {
+			$phpcsFile->addError(sprintf(
+				'Exception class name "%s" must end with "Exception".',
+				$className
+			), $classPointer, self::CODE_NOT_ENDING_WITH_EXCEPTION);
+		}
+	}
+
+	private function checkExceptionDirectoryName(PhpCsFile $phpcsFile, int $classPointer)
+	{
+		$filename = $phpcsFile->getFilename();
+
+		// normalize path for Windows (PHP_CodeSniffer detects it with backslashes on Windows)
+		$filename = str_replace('\\', '/', $filename);
+
+		$pathInfo = pathinfo($filename);
+		$pathSegments = explode('/', $pathInfo['dirname']);
+
+		$exceptionDirectoryName = array_pop($pathSegments);
+
+		if ($exceptionDirectoryName !== $this->exceptionsDirectoryName) {
+			$phpcsFile->addError(sprintf(
+				'Exception file "%s" must be placed in "%s" directory (is in "%s").',
+				$pathInfo['basename'],
+				$this->exceptionsDirectoryName,
+				$exceptionDirectoryName
+			), $classPointer, self::CODE_INCORRECT_EXCEPTION_DIRECTORY);
+		}
+	}
+
+	private function checkThatExceptionIsChainable(PhpCsFile $phpcsFile, int $classPointer)
+	{
+		$constructorPointer = $this->findConstructorMethodPointer($phpcsFile, $classPointer);
+		if ($constructorPointer === null) {
+			return;
+		}
+
+		$typeHints = FunctionHelper::getParametersTypeHints($phpcsFile, $constructorPointer);
+		if (count($typeHints) === 0) {
+			$phpcsFile->addError(
+				'Exception is not chainable. It must have optional \Throwable as last constructor argument.',
+				$constructorPointer,
+				self::CODE_NOT_CHAINABLE
+			);
+			return;
+		}
+		$lastArgument = array_pop($typeHints);
+
+		if ($lastArgument === null) {
+			$phpcsFile->addError(
+				'Exception is not chainable. It must have optional \Throwable as last constructor argument and has none.',
+				$constructorPointer,
+				self::CODE_NOT_CHAINABLE
+			);
+			return;
+		}
+
+		if ($lastArgument->getTypeHint() !== '\Throwable') {
+			$phpcsFile->addError(sprintf(
+				'Exception is not chainable. It must have optional \Throwable as last constructor argument and has "%s".',
+				$lastArgument->getTypeHint()
+			), $constructorPointer, self::CODE_NOT_CHAINABLE);
+			return;
+		}
+	}
+
+	/**
+	 * @param \PHP_CodeSniffer\Files\File $phpcsFile
+	 * @param int $classPointer
+	 * @return int|null
+	 */
+	private function findConstructorMethodPointer(PhpCsFile $phpcsFile, int $classPointer)
+	{
+		$functionPointerToScan = $classPointer;
+		while (($functionPointer = TokenHelper::findNext($phpcsFile, T_FUNCTION, $functionPointerToScan)) !== null) {
+			$functionName = FunctionHelper::getName($phpcsFile, $functionPointer);
+			if ($functionName === '__construct') {
+				return $functionPointer;
+			}
+			$functionPointerToScan = $functionPointer + 1;
+		}
+		return null;
+	}
+
+}
diff --git a/tests/Sniffs/Exceptions/ExceptionDeclarationSniffTest.php b/tests/Sniffs/Exceptions/ExceptionDeclarationSniffTest.php
new file mode 100644
index 0000000..6bcc3d7
--- /dev/null
+++ b/tests/Sniffs/Exceptions/ExceptionDeclarationSniffTest.php
@@ -0,0 +1,225 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+class ExceptionDeclarationSniffTest extends \Consistence\Sniffs\TestCase
+{
+
+	public function testInvalidExceptionName()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/InvalidExceptionName.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertSniffError(
+			$resultFile,
+			7,
+			ExceptionDeclarationSniff::CODE_NOT_ENDING_WITH_EXCEPTION,
+			'Exception class name "InvalidExceptionName" must end with "Exception".'
+		);
+	}
+
+	public function testValidClassName()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/ValidNameException.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertNoSniffError($resultFile, 7);
+	}
+
+	public function testValidClassNameThatExtendsCustomException()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/ValidClassNameThatExtendsCustomException.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertNoSniffError($resultFile, 7);
+	}
+
+	public function testAbstractExceptionWithValidNameException()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/AbstractExceptionWithValidNameException.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertNoSniffError($resultFile, 7);
+	}
+
+	public function testAbstractClassWithInvalidExceptionName()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/AbstractExceptionWithInvalidName.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertSniffError(
+			$resultFile,
+			7,
+			ExceptionDeclarationSniff::CODE_NOT_ENDING_WITH_EXCEPTION,
+			'Exception class name "AbstractExceptionWithInvalidName" must end with "Exception".'
+		);
+	}
+
+	public function testClassThatDoesNotExtendAnything()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/ClassThatDoesNotExtendAnything.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertNoSniffError($resultFile, 7);
+	}
+
+	public function testClassThatExtendsRegularClass()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/ClassThatDoesNotExtendException.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertNoSniffError($resultFile, 7);
+	}
+
+	public function testInterfaceThatDoesNotExtendAnything()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/InterfaceThatDoesNotExtendAnything.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertNoSniffError($resultFile, 7);
+	}
+
+	public function testInterfaceThatDoesNotExtendAnythingException()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/InterfaceThatDoesNotExtendAnythingException.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertNoSniffError($resultFile, 7);
+	}
+
+	public function testInterfaceThatExtendsException()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/InterfaceThatExtendsException.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertNoSniffError($resultFile, 7);
+	}
+
+	public function testInterfaceThatExtendsExceptionIncorrectName()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/InterfaceThatExtendsExceptionIncorrectName.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertSniffError(
+			$resultFile,
+			7,
+			ExceptionDeclarationSniff::CODE_NOT_ENDING_WITH_EXCEPTION,
+			'Exception class name "InterfaceThatExtendsExceptionIncorrectName" must end with "Exception".'
+		);
+	}
+
+	public function testExceptionWithConstructorWithoutParametersIsNotChainable()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/ConstructWithoutParametersException.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertSniffError(
+			$resultFile,
+			10,
+			ExceptionDeclarationSniff::CODE_NOT_CHAINABLE,
+			'Exception is not chainable. It must have optional \Throwable as last constructor argument.'
+		);
+	}
+
+	public function testExceptionWithChainableConstructorIsChainable()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/ChainableConstructorException.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertNoSniffError($resultFile, 10);
+	}
+
+	public function testExceptionWithNonchainableConstructorIsNotChainable()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/NonChainableConstructorException.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertSniffError(
+			$resultFile,
+			10,
+			ExceptionDeclarationSniff::CODE_NOT_CHAINABLE,
+			'Exception is not chainable. It must have optional \Throwable as last constructor argument and has "string".'
+		);
+	}
+
+	public function testExceptionWithConstructorWithoutParameterTypeHintIsNotChainable()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/NonChainableConstructorWithoutParameterTypehintException.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertSniffError(
+			$resultFile,
+			10,
+			ExceptionDeclarationSniff::CODE_NOT_CHAINABLE,
+			'Exception is not chainable. It must have optional \Throwable as last constructor argument and has none.'
+		);
+	}
+
+	public function testExceptionIsPlacedInCorrectDirectory()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/ValidNameException.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertNoSniffError($resultFile, 7);
+	}
+
+	/**
+	 * @requires OS WIN
+	 */
+	public function testExceptionIsPlacedInCorrectDirectoryOnWindows()
+	{
+		// PHP_CodeSniffer detects the path with backslashes on Windows
+		$resultFile = $this->checkFile(__DIR__ . '\data\ValidNameException.php', [
+			'exceptionsDirectoryName' => 'data',
+		]);
+
+		$this->assertNoSniffError($resultFile, 7);
+	}
+
+	public function testExceptionIsPlacedInIncorrectDirectory()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/ValidNameException.php', [
+			'exceptionsDirectoryName' => 'exceptions',
+		]);
+
+		$this->assertSniffError(
+			$resultFile,
+			7,
+			ExceptionDeclarationSniff::CODE_INCORRECT_EXCEPTION_DIRECTORY,
+			'Exception file "ValidNameException.php" must be placed in "exceptions" directory (is in "data").'
+		);
+	}
+
+	public function testExceptionIsPlacedInIncorrectDirectoryCaseSensitively()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/ValidNameException.php', [
+			'exceptionsDirectoryName' => 'Data',
+		]);
+
+		$this->assertSniffError(
+			$resultFile,
+			7,
+			ExceptionDeclarationSniff::CODE_INCORRECT_EXCEPTION_DIRECTORY,
+			'Exception file "ValidNameException.php" must be placed in "Data" directory (is in "data").'
+		);
+	}
+
+}
diff --git a/tests/Sniffs/Exceptions/data/AbstractExceptionWithInvalidName.php b/tests/Sniffs/Exceptions/data/AbstractExceptionWithInvalidName.php
new file mode 100644
index 0000000..a76be7f
--- /dev/null
+++ b/tests/Sniffs/Exceptions/data/AbstractExceptionWithInvalidName.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+abstract class AbstractExceptionWithInvalidName extends \Exception
+{
+
+}
diff --git a/tests/Sniffs/Exceptions/data/AbstractExceptionWithValidNameException.php b/tests/Sniffs/Exceptions/data/AbstractExceptionWithValidNameException.php
new file mode 100644
index 0000000..1ad49ac
--- /dev/null
+++ b/tests/Sniffs/Exceptions/data/AbstractExceptionWithValidNameException.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+abstract class AbstractExceptionWithValidNameException extends \Exception
+{
+
+}
diff --git a/tests/Sniffs/Exceptions/data/ChainableConstructorException.php b/tests/Sniffs/Exceptions/data/ChainableConstructorException.php
new file mode 100644
index 0000000..b5081fe
--- /dev/null
+++ b/tests/Sniffs/Exceptions/data/ChainableConstructorException.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+class ChainableConstructorException extends \Exception
+{
+
+	public function __construct(string $foo, \Throwable $e)
+	{
+		parent::__construct($foo, 0, $e);
+	}
+
+}
diff --git a/tests/Sniffs/Exceptions/data/ClassThatDoesNotExtendAnything.php b/tests/Sniffs/Exceptions/data/ClassThatDoesNotExtendAnything.php
new file mode 100644
index 0000000..acf27c7
--- /dev/null
+++ b/tests/Sniffs/Exceptions/data/ClassThatDoesNotExtendAnything.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+class ClassThatDoesNotExtendAnything
+{
+
+}
diff --git a/tests/Sniffs/Exceptions/data/ClassThatDoesNotExtendException.php b/tests/Sniffs/Exceptions/data/ClassThatDoesNotExtendException.php
new file mode 100644
index 0000000..544993f
--- /dev/null
+++ b/tests/Sniffs/Exceptions/data/ClassThatDoesNotExtendException.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+class ClassThatDoesNotExtendException extends \Consistence\Sniffs\Exceptions\NotAnExceptionClass
+{
+
+}
diff --git a/tests/Sniffs/Exceptions/data/ConstructWithoutParametersException.php b/tests/Sniffs/Exceptions/data/ConstructWithoutParametersException.php
new file mode 100644
index 0000000..02abc2c
--- /dev/null
+++ b/tests/Sniffs/Exceptions/data/ConstructWithoutParametersException.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+class ConstructWithoutParametersException extends \Exception
+{
+
+	public function __construct()
+	{
+		parent::__construct('error', 0, null);
+	}
+
+}
diff --git a/tests/Sniffs/Exceptions/data/InterfaceThatDoesNotExtendAnything.php b/tests/Sniffs/Exceptions/data/InterfaceThatDoesNotExtendAnything.php
new file mode 100644
index 0000000..c8a60e6
--- /dev/null
+++ b/tests/Sniffs/Exceptions/data/InterfaceThatDoesNotExtendAnything.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+interface InterfaceThatDoesNotExtendAnything
+{
+
+	public function fooMethod(): string;
+
+}
diff --git a/tests/Sniffs/Exceptions/data/InterfaceThatDoesNotExtendAnythingException.php b/tests/Sniffs/Exceptions/data/InterfaceThatDoesNotExtendAnythingException.php
new file mode 100644
index 0000000..1a04815
--- /dev/null
+++ b/tests/Sniffs/Exceptions/data/InterfaceThatDoesNotExtendAnythingException.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+interface InterfaceThatDoesNotExtendAnythingException
+{
+
+	public function fooMethod(): string;
+
+}
diff --git a/tests/Sniffs/Exceptions/data/InterfaceThatExtendsException.php b/tests/Sniffs/Exceptions/data/InterfaceThatExtendsException.php
new file mode 100644
index 0000000..45266c6
--- /dev/null
+++ b/tests/Sniffs/Exceptions/data/InterfaceThatExtendsException.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+interface InterfaceThatExtendsException extends \Consistence\Sniffs\Exceptions\InterfaceThatDoesNotExtendAnythingException
+{
+
+	public function extraString(): string;
+
+}
diff --git a/tests/Sniffs/Exceptions/data/InterfaceThatExtendsExceptionIncorrectName.php b/tests/Sniffs/Exceptions/data/InterfaceThatExtendsExceptionIncorrectName.php
new file mode 100644
index 0000000..ac0846a
--- /dev/null
+++ b/tests/Sniffs/Exceptions/data/InterfaceThatExtendsExceptionIncorrectName.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+interface InterfaceThatExtendsExceptionIncorrectName extends \Consistence\Sniffs\Exceptions\InterfaceThatDoesNotExtendAnythingException
+{
+
+	public function extraString(): string;
+
+}
diff --git a/tests/Sniffs/Exceptions/data/InvalidExceptionName.php b/tests/Sniffs/Exceptions/data/InvalidExceptionName.php
new file mode 100644
index 0000000..d6d8aee
--- /dev/null
+++ b/tests/Sniffs/Exceptions/data/InvalidExceptionName.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+class InvalidExceptionName extends \Exception
+{
+
+}
diff --git a/tests/Sniffs/Exceptions/data/NonChainableConstructorException.php b/tests/Sniffs/Exceptions/data/NonChainableConstructorException.php
new file mode 100644
index 0000000..2f6f6f9
--- /dev/null
+++ b/tests/Sniffs/Exceptions/data/NonChainableConstructorException.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+class NonChainableConstructorException extends \Exception
+{
+
+	public function __construct(string $foo)
+	{
+		parent::__construct($foo, 0, null);
+	}
+
+}
diff --git a/tests/Sniffs/Exceptions/data/NonChainableConstructorWithoutParameterTypehintException.php b/tests/Sniffs/Exceptions/data/NonChainableConstructorWithoutParameterTypehintException.php
new file mode 100644
index 0000000..817e56d
--- /dev/null
+++ b/tests/Sniffs/Exceptions/data/NonChainableConstructorWithoutParameterTypehintException.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+class NonChainableConstructorWithoutParameterTypehintException extends \Exception
+{
+
+	public function __construct($foo, $bar)
+	{
+		parent::__construct($foo, 0, null);
+	}
+
+}
diff --git a/tests/Sniffs/Exceptions/data/ValidClassNameThatExtendsCustomException.php b/tests/Sniffs/Exceptions/data/ValidClassNameThatExtendsCustomException.php
new file mode 100644
index 0000000..ed0982d
--- /dev/null
+++ b/tests/Sniffs/Exceptions/data/ValidClassNameThatExtendsCustomException.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+class ValidClassNameThatExtendsCustomException extends \Consistence\Sniffs\Exceptions\ValidNameException
+{
+
+}
diff --git a/tests/Sniffs/Exceptions/data/ValidNameException.php b/tests/Sniffs/Exceptions/data/ValidNameException.php
new file mode 100644
index 0000000..daf9b18
--- /dev/null
+++ b/tests/Sniffs/Exceptions/data/ValidNameException.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Consistence\Sniffs\Exceptions;
+
+class ValidNameException extends \Exception
+{
+
+}
diff --git a/tests/Sniffs/TestCase.php b/tests/Sniffs/TestCase.php
index 7558267..cd6510d 100644
--- a/tests/Sniffs/TestCase.php
+++ b/tests/Sniffs/TestCase.php
@@ -22,7 +22,15 @@ public function __construct(string $name = null, array $data = [], string $dataN
 		parent::__construct($name, $data, $dataName);
 	}
 
-	protected function checkFile(string $filePath): PhpCsFile
+	/**
+	 * @param string $filePath
+	 * @param mixed[] $sniffProperties
+	 * @return \PHP_CodeSniffer\Files\File
+	 */
+	protected function checkFile(
+		string $filePath,
+		array $sniffProperties = []
+	): PhpCsFile
 	{
 		if (!is_readable($filePath)) {
 			throw new \Exception(sprintf(
@@ -38,6 +46,10 @@ protected function checkFile(string $filePath): PhpCsFile
 
 		$codeSniffer->init();
 
+		if (count($sniffProperties) > 0) {
+			$codeSniffer->ruleset->ruleset[$this->getSniffName()]['properties'] = $sniffProperties;
+		}
+
 		$codeSniffer->ruleset->sniffs = [$this->getSniffClassName() => $this->getSniffClassName()];
 		$codeSniffer->ruleset->populateTokenListeners();