diff --git a/tmux.h b/tmux.h
index 1c643534..61027b98 100644
--- a/tmux.h
+++ b/tmux.h
@@ -39,9 +39,6 @@
 extern char    *__progname;
 extern char   **environ;
 
-extern char    *__progname;
-extern char   **environ;
-
 /* Default global configuration file. */
 #define TMUX_CONF "/etc/tmux.conf"