diff --git a/src/unix/aix.c b/src/unix/aix.c
index 07f81fcf0..06f19a4fc 100644
--- a/src/unix/aix.c
+++ b/src/unix/aix.c
@@ -921,6 +921,7 @@ int uv_uptime(double* uptime) {
   size_t entries = 0;
   time_t boot_time;
 
+  boot_time = 0;
   utmpname(UTMP_FILE);
 
   setutent();