diff --git a/include/libtorrent/kademlia/observer.hpp b/include/libtorrent/kademlia/observer.hpp
index d8d217961..8d2f8a9ee 100644
--- a/include/libtorrent/kademlia/observer.hpp
+++ b/include/libtorrent/kademlia/observer.hpp
@@ -36,6 +36,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <boost/pool/pool.hpp>
 #include <boost/detail/atomic_count.hpp>
 #include <boost/intrusive_ptr.hpp>
+#include <boost/cstdint.hpp>
 
 namespace libtorrent {
 namespace dht {
@@ -89,7 +90,7 @@ struct observer : boost::noncopyable
 #else
 	address_v4 target_addr;
 #endif
-	uint16_t port;
+	boost::uint16_t port;
 	udp::endpoint target_ep() const { return udp::endpoint(target_addr, port); }
 	ptime sent;
 #ifdef TORRENT_DEBUG