diff --git a/src/uvw/thread.cpp b/src/uvw/thread.cpp
index c3287d88..1b7815f4 100644
--- a/src/uvw/thread.cpp
+++ b/src/uvw/thread.cpp
@@ -40,7 +40,7 @@ UVW_INLINE bool Thread::run() noexcept {
 
 
 UVW_INLINE bool Thread::run(Flags<Options> opts, std::size_t stack) noexcept {
-    uv_thread_options_t params{opts, stack};
+    uv_thread_options_t params{static_cast<unsigned int>(opts), stack};
     return (0 == uv_thread_create_ex(get(), &params, &createCallback, this));
 }