diff --git a/lib/DeonApi.ts b/lib/DeonApi.ts
index f0e2e84..786fb9e 100644
--- a/lib/DeonApi.ts
+++ b/lib/DeonApi.ts
@@ -41,7 +41,7 @@ export interface IdentifiedDeonApi {
     tag?: D.Tag,
   ): Promise<D.Tag>;
 
-  terminateContract(id: string): Promise<void>;
+  terminateContract(id: string, terminatedAtTime: Date, description: String): Promise<void>;
 
   postReport(
     i: D.EvaluateExpressionInput,
diff --git a/lib/DeonApiMock.ts b/lib/DeonApiMock.ts
index f0ddbef..b9c1cd5 100644
--- a/lib/DeonApiMock.ts
+++ b/lib/DeonApiMock.ts
@@ -70,7 +70,7 @@ export const identifiedApiMock: IdentifiedDeonApi = {
     _2?: Tag,
   ): Promise<Tag> => Promise.reject(),
 
-  terminateContract: (_0: string): Promise<void> => Promise.reject(),
+  terminateContract: (_0: string, _1: Date, _2: String): Promise<void> => Promise.reject(),
 
   postReport: (
     _0: EvaluateExpressionInput,
diff --git a/lib/DeonData.ts b/lib/DeonData.ts
index cded14d..07a3249 100644
--- a/lib/DeonData.ts
+++ b/lib/DeonData.ts
@@ -57,6 +57,11 @@ export interface InstantiationOutput {
   tag: string;
 }
 
+export interface TerminationInput {
+  terminatedAtTime: Date;
+  description: string;
+}
+
 export interface CheckExpressionInput {
   csl: string;
 }
@@ -71,6 +76,11 @@ export interface EvaluateReportInput {
   arguments: Value[];
 }
 
+export interface TerminationInput {
+  description: string;
+  terminatedAtTime: Date;
+}
+
 export interface NodeInfoOutput {
   ledgerType: string;
   nodeName: string;
@@ -563,6 +573,7 @@ export interface ReifiedValBinding {
 /* Contracts */
 export interface TerminationDetails {
   terminatedAtTime: Date;
+  description: String;
   requestingPeer: ExternalObject;
 }
 
diff --git a/lib/DeonRestClient.ts b/lib/DeonRestClient.ts
index 301cd24..2eb4303 100644
--- a/lib/DeonRestClient.ts
+++ b/lib/DeonRestClient.ts
@@ -32,6 +32,7 @@ import {
   OntologyRequest,
   EntrypointSignatureRequest,
   OntologyAndEntrypointSignatures,
+  TerminationInput,
 } from './DeonData';
 import { HttpClient, Response } from './HttpClient';
 import { ExternalObject } from './ExternalObject';
@@ -206,8 +207,12 @@ export class IdentifiedDeonRestClient implements IdentifiedDeonApi {
     return this.http.post(`/contracts/${idString(id)}/${tag != null ? `${tag}/` : ''}events`, event)
       .then(possiblyBadRequestOrNotFound);
   }
-  terminateContract(id: string): Promise<void> {
-    return this.http.post(`/contracts/${id}/terminateContract`)
+  terminateContract(id: string, terminatedAtTime: Date, description: string): Promise<void> {
+    const terminationInput : TerminationInput = {
+      terminatedAtTime,
+      description,
+    };
+    return this.http.post(`/contracts/${id}/terminateContract`, terminationInput)
       .then(possiblyBadRequestOrNotFound);
   }
   postReport(i: EvaluateExpressionInput, id?: string): Promise<Value> {