diff --git a/vtkm/cont/kokkos/internal/DeviceAdapterAlgorithmKokkos.h b/vtkm/cont/kokkos/internal/DeviceAdapterAlgorithmKokkos.h
index 24c9e1a5e..a42f3a094 100644
--- a/vtkm/cont/kokkos/internal/DeviceAdapterAlgorithmKokkos.h
+++ b/vtkm/cont/kokkos/internal/DeviceAdapterAlgorithmKokkos.h
@@ -151,7 +151,7 @@ public:
                                                           ErrorMessageMaxLength);
     functor.SetErrorMessageBuffer(errorMessage);
 
-    Kokkos::parallel_for(numInstances, functor);
+    Kokkos::parallel_for(static_cast<std::size_t>(numInstances), functor);
 
     CheckForErrors(errorMessageStorage);
   }