diff --git a/src/main-misc.c b/src/main-misc.c
index ab7b5644..b8386037 100644
--- a/src/main-misc.c
+++ b/src/main-misc.c
@@ -47,6 +47,7 @@
 #include <proc-search.h>
 #include <ipc.pb-c.h>
 #include <script-list.h>
+#include <inttypes.h>
 
 #ifdef HAVE_MALLOC_TRIM
 # include <malloc.h>
@@ -173,7 +174,7 @@ struct proc_st *ctmp;
  */
 void remove_proc(main_server_st * s, struct proc_st *proc, unsigned flags)
 {
-	mslog(s, proc, LOG_INFO, "user disconnected (rx: %lu, tx: %lu)", proc->bytes_in, proc->bytes_out);
+	mslog(s, proc, LOG_INFO, "user disconnected (rx: %"PRIu64", tx: %"PRIu64")", proc->bytes_in, proc->bytes_out);
 
 	list_del(&proc->list);
 	s->active_clients--;