diff --git a/testdata/fuzz/FuzzNewChooser/a547669aeb7ca0ca b/testdata/fuzz/FuzzNewChooser/a547669aeb7ca0ca
new file mode 100644
index 0000000..e4a5f9c
--- /dev/null
+++ b/testdata/fuzz/FuzzNewChooser/a547669aeb7ca0ca
@@ -0,0 +1,2 @@
+go test fuzz v1
+[]byte("0000000\x8f00000000")
diff --git a/weightedrand.go b/weightedrand.go
index 3320121..52fd89b 100644
--- a/weightedrand.go
+++ b/weightedrand.go
@@ -48,11 +48,16 @@ func NewChooser[T any, W integer](choices ...Choice[T, W]) (*Chooser[T, W], erro
 	totals := make([]int, len(choices))
 	runningTotal := 0
 	for i, c := range choices {
-		weight := int(c.Weight)
-		if weight < 0 {
+		if c.Weight < 0 {
 			continue // ignore negative weights, can never be picked
 		}
 
+		// case of single ~uint64 or similar value that exceeds maxInt on its own
+		if uint64(c.Weight) >= maxInt {
+			return nil, errWeightOverflow
+		}
+
+		weight := int(c.Weight) // convert weight to int for internal counter usage
 		if (maxInt - runningTotal) <= weight {
 			return nil, errWeightOverflow
 		}
@@ -68,8 +73,9 @@ func NewChooser[T any, W integer](choices ...Choice[T, W]) (*Chooser[T, W], erro
 }
 
 const (
-	intSize = 32 << (^uint(0) >> 63) // cf. strconv.IntSize
-	maxInt  = 1<<(intSize-1) - 1
+	intSize   = 32 << (^uint(0) >> 63) // cf. strconv.IntSize
+	maxInt    = 1<<(intSize-1) - 1
+	maxUint64 = 1<<64 - 1
 )
 
 // Possible errors returned by NewChooser, preventing the creation of a Chooser
diff --git a/weightedrand_test.go b/weightedrand_test.go
index 824eeb0..0eb4206 100644
--- a/weightedrand_test.go
+++ b/weightedrand_test.go
@@ -81,10 +81,42 @@ func TestNewChooser(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			_, err := NewChooser(tt.cs...)
+			c, err := NewChooser(tt.cs...)
 			if err != tt.wantErr {
 				t.Errorf("NewChooser() error = %v, wantErr %v", err, tt.wantErr)
 			}
+
+			if err == nil { // run a few Picks to make sure there are no panics
+				for i := 0; i < 10; i++ {
+					_ = c.Pick()
+				}
+			}
+		})
+	}
+
+	u64tests := []struct {
+		name    string
+		cs      []Choice[rune, uint64]
+		wantErr error
+	}{
+		{
+			name:    "weight overflow from single uint64 exceeding system maxInt",
+			cs:      []Choice[rune, uint64]{{Item: 'a', Weight: maxInt + 1}},
+			wantErr: errWeightOverflow,
+		},
+	}
+	for _, tt := range u64tests {
+		t.Run(tt.name, func(t *testing.T) {
+			c, err := NewChooser(tt.cs...)
+			if err != tt.wantErr {
+				t.Errorf("NewChooser() error = %v, wantErr %v", err, tt.wantErr)
+			}
+
+			if err == nil { // run a few Picks to make sure there are no panics
+				for i := 0; i < 10; i++ {
+					_ = c.Pick()
+				}
+			}
 		})
 	}
 }