diff --git a/src/SwaggerProvider.DesignTime/v2/OperationCompiler.fs b/src/SwaggerProvider.DesignTime/v2/OperationCompiler.fs
index 5e266c9..8afd8ec 100644
--- a/src/SwaggerProvider.DesignTime/v2/OperationCompiler.fs
+++ b/src/SwaggerProvider.DesignTime/v2/OperationCompiler.fs
@@ -56,6 +56,18 @@ type OperationCompiler(schema: SwaggerObject, defCompiler: DefinitionCompiler, i
             // reverse it again so that all required properties come first
             |> List.rev
 
+        // Append an optional CancellationToken parameter last (after all OpenAPI params).
+        // Using a UniqueNameGenerator avoids collisions with existing parameter names.
+        let ctArgIndex = List.length parameters
+
+        let parameters =
+            let scope = UniqueNameGenerator()
+            parameters |> List.iter(fun p -> scope.MakeUnique p.Name |> ignore)
+            let ctName = scope.MakeUnique "cancellationToken"
+
+            parameters
+            @ [ ProvidedParameter(ctName, typeof<Threading.CancellationToken>, false, null) ]
+
         // find the inner type value
         let retTy =
             let okResponse =
@@ -110,9 +122,15 @@ type OperationCompiler(schema: SwaggerObject, defCompiler: DefinitionCompiler, i
                                        "Content-Type", MediaTypes.ApplicationJson |]
                             @>
 
-                        // Locates parameters matching the arguments
+                        // Extract CancellationToken (appended at ctArgIndex) and separate from OpenAPI params.
+                        let allArgs = List.tail args // skip `this` param
+                        let ct = List.item ctArgIndex allArgs |> Expr.Cast<Threading.CancellationToken>
+
+                        // Locates parameters matching the arguments (excluding CT arg)
                         let parameters =
-                            List.tail args // skip `this` param
+                            allArgs
+                            |> List.indexed
+                            |> List.choose(fun (i, arg) -> if i = ctArgIndex then None else Some arg)
                             |> List.map (function
                                 | ShapeVar sVar as expr ->
                                     let param =
@@ -212,11 +230,7 @@ type OperationCompiler(schema: SwaggerObject, defCompiler: DefinitionCompiler, i
                             <@
                                 let msg = %httpRequestMessageWithPayload
                                 RuntimeHelpers.fillHeaders msg %heads
-
-                                task {
-                                    let! response = (%this).HttpClient.SendAsync(msg)
-                                    return response.EnsureSuccessStatusCode().Content
-                                }
+                                (%this).CallAsync(msg, [||], [||], %ct)
                             @>
 
                         let responseObj =
diff --git a/tests/SwaggerProvider.ProviderTests/SwaggerProvider.ProviderTests.fsproj b/tests/SwaggerProvider.ProviderTests/SwaggerProvider.ProviderTests.fsproj
index 14c5674..c79cb40 100644
--- a/tests/SwaggerProvider.ProviderTests/SwaggerProvider.ProviderTests.fsproj
+++ b/tests/SwaggerProvider.ProviderTests/SwaggerProvider.ProviderTests.fsproj
@@ -12,6 +12,7 @@
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="v2\Swashbuckle.ReturnControllers.Tests.fs" />
+    <Compile Include="v2\Swashbuckle.CancellationToken.Tests.fs" />
     <Compile Include="v2\Swashbuckle.UpdateControllers.Tests.fs" />
     <Compile Include="v2\Swashbuckle.ResourceControllers.Tests.fs" />
     <Compile Include="v2\Swashbuckle.NoContentControllers.Tests.fs" />
diff --git a/tests/SwaggerProvider.ProviderTests/v2/Swashbuckle.CancellationToken.Tests.fs b/tests/SwaggerProvider.ProviderTests/v2/Swashbuckle.CancellationToken.Tests.fs
new file mode 100644
index 0000000..a0a29ac
--- /dev/null
+++ b/tests/SwaggerProvider.ProviderTests/v2/Swashbuckle.CancellationToken.Tests.fs
@@ -0,0 +1,120 @@
+module Swashbuckle.v2.CancellationTokenTests
+
+open Xunit
+open FsUnitTyped
+open System
+open System.Net.Http
+open System.Threading
+open SwaggerProvider
+open Swashbuckle.v2.ReturnControllersTests
+
+type WebAPIAsync =
+    SwaggerClientProvider<"http://localhost:5000/swagger/v1/swagger.json", IgnoreOperationId=true, SsrfProtection=false, PreferAsync=true>
+
+let apiAsync =
+    let handler = new HttpClientHandler(UseCookies = false)
+
+    let client =
+        new HttpClient(handler, true, BaseAddress = Uri("http://localhost:5000"))
+
+    WebAPIAsync.Client(client)
+
+[<Fact>]
+let ``v2 Call generated method without CancellationToken uses default token``() =
+    task {
+        let! result = api.GetApiReturnBoolean()
+        result |> shouldEqual true
+    }
+
+[<Fact>]
+let ``v2 Call generated method with explicit CancellationToken None``() =
+    task {
+        let! result = api.GetApiReturnBoolean(CancellationToken.None)
+        result |> shouldEqual true
+    }
+
+[<Fact>]
+let ``v2 Call generated method with valid CancellationTokenSource token``() =
+    task {
+        use cts = new CancellationTokenSource()
+        let! result = api.GetApiReturnInt32(cts.Token)
+        result |> shouldEqual 42
+    }
+
+[<Fact>]
+let ``v2 Call generated method with already-cancelled token raises OperationCanceledException``() =
+    task {
+        use cts = new CancellationTokenSource()
+        cts.Cancel()
+
+        try
+            let! _ = api.GetApiReturnString(cts.Token)
+            failwith "Expected OperationCanceledException"
+        with
+        | :? OperationCanceledException -> ()
+        | :? System.AggregateException as aex when (aex.InnerException :? OperationCanceledException) -> ()
+    }
+
+[<Fact>]
+let ``v2 Call POST generated method with explicit CancellationToken None``() =
+    task {
+        let! result = api.PostApiReturnString(CancellationToken.None)
+        result |> shouldEqual "Hello world"
+    }
+
+[<Fact>]
+let ``v2 Call async generated method without CancellationToken uses default token``() =
+    async {
+        let! result = apiAsync.GetApiReturnBoolean()
+        result |> shouldEqual true
+    }
+    |> Async.StartAsTask
+
+[<Fact>]
+let ``v2 Call method with required param and explicit CancellationToken``() =
+    task {
+        use cts = new CancellationTokenSource()
+        let! result = api.GetApiUpdateString("Serge", cts.Token)
+        result |> shouldEqual "Hello, Serge"
+    }
+
+[<Fact>]
+let ``v2 Call method with optional param and explicit CancellationToken``() =
+    task {
+        use cts = new CancellationTokenSource()
+        let! result = api.GetApiUpdateBool(Some true, cts.Token)
+        result |> shouldEqual false
+    }
+
+[<Fact>]
+let ``v2 Call async generated method with explicit CancellationToken``() =
+    async {
+        use cts = new CancellationTokenSource()
+        let! result = apiAsync.GetApiReturnInt32(cts.Token)
+        result |> shouldEqual 42
+    }
+    |> Async.StartAsTask
+
+[<Fact>]
+let ``v2 Call async generated method with already-cancelled token raises OperationCanceledException``() =
+    async {
+        use cts = new CancellationTokenSource()
+        cts.Cancel()
+
+        try
+            let! _ = apiAsync.GetApiReturnString(cts.Token)
+            failwith "Expected OperationCanceledException"
+        with
+        | :? OperationCanceledException -> ()
+        | :? AggregateException as aex when (aex.InnerException :? OperationCanceledException) -> ()
+    }
+    |> Async.StartAsTask
+
+[<Fact>]
+let ``v2 Call async POST generated method with explicit CancellationToken``() =
+    async {
+        use cts = new CancellationTokenSource()
+        let! result = apiAsync.PostApiReturnString(cts.Token)
+        result |> shouldEqual "Hello world"
+    }
+    |> Async.StartAsTask