diff --git a/README.md b/README.md
index ba723e4..d67f50e 100644
--- a/README.md
+++ b/README.md
@@ -25,7 +25,7 @@ A full example is available in the CustomLibrary.ProblemDetails.Sample folder or
 | 409 | ConflictException | available |
 | 422 | UnprocessableEntityException | available |
 | 500 | InternalServerErrorException | available |
-| 501 | NotImplementedException | coming soon |
+| 501 | NotImplementedException | available |
 | 502 | BadGatewayException | coming soon |
 | 503 | ServiceUnavailableException | coming soon |
 | 504 | GatewayTimeoutException | coming soon |
diff --git a/src/CustomLibrary.ProblemDetails.Sample/Controllers/TestController.cs b/src/CustomLibrary.ProblemDetails.Sample/Controllers/TestController.cs
index 49ecbba..8e7543f 100644
--- a/src/CustomLibrary.ProblemDetails.Sample/Controllers/TestController.cs
+++ b/src/CustomLibrary.ProblemDetails.Sample/Controllers/TestController.cs
@@ -165,4 +165,18 @@ public async Task<IActionResult> GetExceptionInternalServerErrorAsync()
             return ResponseException.InternalServerError(HttpContext, exc);
         }
     }
+
+    [HttpGet("NotImplemented")]
+    public async Task<IActionResult> GetExceptionNotImplementedAsync()
+    {
+        try
+        {
+            await Task.Delay(500);
+            throw new Exception.NotImplementedException("Not Implemented");
+        }
+        catch (Exception.NotImplementedException exc)
+        {
+            return ResponseException.NotImplemented(HttpContext, exc);
+        }
+    }
 }
\ No newline at end of file
diff --git a/src/CustomLibrary.ProblemDetails/Exception/NotImplementedException.cs b/src/CustomLibrary.ProblemDetails/Exception/NotImplementedException.cs
new file mode 100644
index 0000000..1dcda28
--- /dev/null
+++ b/src/CustomLibrary.ProblemDetails/Exception/NotImplementedException.cs
@@ -0,0 +1,16 @@
+namespace CustomLibrary.ProblemDetails.Exception;
+
+public class NotImplementedException : System.Exception
+{
+    public NotImplementedException()
+    {
+    }
+
+    public NotImplementedException(string message) : base(message)
+    {
+    }
+
+    public NotImplementedException(string message, System.Exception innerException) : base(message, innerException)
+    {
+    }
+}
\ No newline at end of file
diff --git a/src/CustomLibrary.ProblemDetails/ResponseException.cs b/src/CustomLibrary.ProblemDetails/ResponseException.cs
index fef63ed..a2cf791 100644
--- a/src/CustomLibrary.ProblemDetails/ResponseException.cs
+++ b/src/CustomLibrary.ProblemDetails/ResponseException.cs
@@ -309,4 +309,32 @@ public static ObjectResult InternalServerError(HttpContext httpContext, System.E
 
         return result;
     }
+
+    public static ObjectResult NotImplemented(HttpContext httpContext, System.Exception exc, List<string> validationError = null)
+    {
+        var statusCode = StatusCodes.Status501NotImplemented;
+        var problemDetails = new CustomProblemDetails
+        {
+            Status = statusCode,
+            Detail = exc.Message,
+            Type = $"https://httpstatuses.com/{statusCode}",
+            Instance = httpContext.Request.Path,
+            Title = "InternalServerError"
+        };
+
+        problemDetails.Extensions.Add("traceId", Activity.Current?.Id ?? httpContext.TraceIdentifier);
+        //problemDetails.Extensions.Add("errors", exc.Message);
+
+        if (validationError?.Any() ?? false)
+        {
+            problemDetails.Extensions.Add("errors", validationError);
+        }
+
+        var result = new ObjectResult(problemDetails)
+        {
+            StatusCode = statusCode
+        };
+
+        return result;
+    }
 }
\ No newline at end of file