diff --git a/include/uv-private/uv-unix.h b/include/uv-private/uv-unix.h
index fed7f8de..49e81bcf 100644
--- a/include/uv-private/uv-unix.h
+++ b/include/uv-private/uv-unix.h
@@ -131,8 +131,7 @@ struct uv__io_s {
 
 #define UV_UDP_SEND_PRIVATE_FIELDS  \
   ngx_queue_t queue;                \
-  struct sockaddr_storage addr;     \
-  socklen_t addrlen;                \
+  struct sockaddr_in6 addr;         \
   uv_buf_t* bufs;                   \
   int bufcnt;                       \
   ssize_t status;                   \
diff --git a/src/unix/udp.c b/src/unix/udp.c
index 495939c7..523d2823 100644
--- a/src/unix/udp.c
+++ b/src/unix/udp.c
@@ -116,7 +116,8 @@ static void uv__udp_run_pending(uv_udp_t* handle) {
 
     memset(&h, 0, sizeof h);
     h.msg_name = &req->addr;
-    h.msg_namelen = req->addrlen;
+    h.msg_namelen = (req->addr.sin6_family == AF_INET6 ?
+      sizeof(struct sockaddr_in6) : sizeof(struct sockaddr_in));
     h.msg_iov = (struct iovec*)req->bufs;
     h.msg_iovlen = req->bufcnt;
 
@@ -415,8 +416,8 @@ static int uv__udp_send(uv_udp_send_t* req,
 
   uv__req_init(handle->loop, req, UV_UDP_SEND);
 
+  assert(addrlen <= sizeof(req->addr));
   memcpy(&req->addr, addr, addrlen);
-  req->addrlen = addrlen;
   req->send_cb = send_cb;
   req->handle = handle;
   req->bufcnt = bufcnt;
diff --git a/test/benchmark-sizes.c b/test/benchmark-sizes.c
index 09e06e8f..6d16e3ca 100644
--- a/test/benchmark-sizes.c
+++ b/test/benchmark-sizes.c
@@ -27,6 +27,7 @@ BENCHMARK_IMPL(sizes) {
   LOGF("uv_shutdown_t: %u bytes\n", (unsigned int) sizeof(uv_shutdown_t));
   LOGF("uv_write_t: %u bytes\n", (unsigned int) sizeof(uv_write_t));
   LOGF("uv_connect_t: %u bytes\n", (unsigned int) sizeof(uv_connect_t));
+  LOGF("uv_udp_send_t: %u bytes\n", (unsigned int) sizeof(uv_udp_send_t));
   LOGF("uv_tcp_t: %u bytes\n", (unsigned int) sizeof(uv_tcp_t));
   LOGF("uv_pipe_t: %u bytes\n", (unsigned int) sizeof(uv_pipe_t));
   LOGF("uv_tty_t: %u bytes\n", (unsigned int) sizeof(uv_tty_t));