diff --git a/lib/windows/winlean.nim b/lib/windows/winlean.nim
index 39f2be61da..9f04bab355 100644
--- a/lib/windows/winlean.nim
+++ b/lib/windows/winlean.nim
@@ -690,6 +690,7 @@ const
   ERROR_IO_PENDING* = 997 # a.k.a WSA_IO_PENDING
   FILE_FLAG_OVERLAPPED* = 1073741824
   WSAECONNABORTED* = 10053
+  WSAEADDRINUSE* = 10048
   WSAECONNRESET* = 10054
   WSAEDISCON* = 10101
   WSAENETRESET* = 10052