diff --git a/src/csharp/Grpc.Core/Internal/UnmanagedLibrary.cs b/src/csharp/Grpc.Core/Internal/UnmanagedLibrary.cs
index 31e14028494719085a11d12c37c7b6239d38be46..1553bdd687e6e2631851974a591cd8f18ee60d15 100644
--- a/src/csharp/Grpc.Core/Internal/UnmanagedLibrary.cs
+++ b/src/csharp/Grpc.Core/Internal/UnmanagedLibrary.cs
@@ -134,7 +134,11 @@ namespace Grpc.Core.Internal
             {
                 throw new MissingMethodException(string.Format("The native method \"{0}\" does not exist", methodName));
             }
-            return Marshal.GetDelegateForFunctionPointer(ptr, typeof(T)) as T;
+#if NETSTANDARD1_5
+            return Marshal.GetDelegateForFunctionPointer<T>(ptr);  // non-generic version is obsolete
+#else
+            return Marshal.GetDelegateForFunctionPointer(ptr, typeof(T)) as T;  // generic version not available in .NET45
+#endif
         }
 
         /// <summary>