diff --git a/include/uv.h b/include/uv.h
index 849d0cd8..e52ae643 100644
--- a/include/uv.h
+++ b/include/uv.h
@@ -432,7 +432,7 @@ UV_EXTERN void uv_close(uv_handle_t* handle, uv_close_cb close_cb);
  * base and len members of the uv_buf_t struct. The user is responsible for
  * freeing base after the uv_buf_t is done. Return struct passed by value.
  */
-UV_EXTERN uv_buf_t uv_buf_init(char* base, size_t len);
+UV_EXTERN uv_buf_t uv_buf_init(char* base, unsigned int len);
 
 
 /*
diff --git a/src/uv-common.c b/src/uv-common.c
index 761133a6..48f850c7 100644
--- a/src/uv-common.c
+++ b/src/uv-common.c
@@ -87,7 +87,7 @@ size_t uv_strlcat(char* dst, const char* src, size_t size) {
 }
 
 
-uv_buf_t uv_buf_init(char* base, size_t len) {
+uv_buf_t uv_buf_init(char* base, unsigned int len) {
   uv_buf_t buf;
   buf.base = base;
   buf.len = len;