diff --git a/src/win/core.c b/src/win/core.c
index 1938c0ad..b7a066eb 100644
--- a/src/win/core.c
+++ b/src/win/core.c
@@ -130,7 +130,7 @@ static void uv_poll_ex(int block) {
   uv_req_t* req;
   OVERLAPPED_ENTRY overlappeds[64];
   ULONG count;
-  int i;
+  ULONG i;
 
   if (block) {
     timeout = uv_get_poll_timeout();
diff --git a/test/benchmark-ping-pongs.c b/test/benchmark-ping-pongs.c
index 721e8c82..53cea782 100644
--- a/test/benchmark-ping-pongs.c
+++ b/test/benchmark-ping-pongs.c
@@ -124,7 +124,7 @@ static void pinger_shutdown_cb(uv_shutdown_t* req, int status) {
 
 
 static void pinger_read_cb(uv_stream_t* tcp, ssize_t nread, uv_buf_t buf) {
-  unsigned int i;
+  ssize_t i;
   pinger_t* pinger;
 
   pinger = (pinger_t*)tcp->data;
diff --git a/test/test-ping-pong.c b/test/test-ping-pong.c
index d99e2052..26718cd3 100644
--- a/test/test-ping-pong.c
+++ b/test/test-ping-pong.c
@@ -94,7 +94,7 @@ static void pinger_write_ping(pinger_t* pinger) {
 
 
 static void pinger_read_cb(uv_stream_t* stream, ssize_t nread, uv_buf_t buf) {
-  unsigned int i;
+  ssize_t i;
   pinger_t* pinger;
 
   pinger = (pinger_t*)stream->data;