diff --git a/include/uv.h b/include/uv.h
index e6cc61bf..ee94397a 100644
--- a/include/uv.h
+++ b/include/uv.h
@@ -143,6 +143,7 @@ extern "C" {
   XX(EREMOTEIO, "remote I/O error")                                           \
   XX(ENOTTY, "inappropriate ioctl for device")                                \
   XX(EFTYPE, "inappropriate file type or format")                             \
+  XX(EILSEQ, "illegal byte sequence")                                         \
 
 #define UV_HANDLE_TYPE_MAP(XX)                                                \
   XX(ASYNC, async)                                                            \
diff --git a/include/uv/errno.h b/include/uv/errno.h
index 8eeb95de..165fd11c 100644
--- a/include/uv/errno.h
+++ b/include/uv/errno.h
@@ -439,5 +439,10 @@
 # define UV__EFTYPE (-4028)
 #endif
 
+#if defined(EILSEQ) && !defined(_WIN32)
+# define UV__EILSEQ UV__ERR(EILSEQ)
+#else
+# define UV__EILSEQ (-4027)
+#endif
 
 #endif /* UV_ERRNO_H_ */