diff --git a/doc/api/os.markdown b/doc/api/os.markdown
index ae620e895c..177f499249 100644
--- a/doc/api/os.markdown
+++ b/doc/api/os.markdown
@@ -41,6 +41,7 @@ Returns the system uptime in seconds.
 ## os.loadavg()
 
 Returns an array containing the 1, 5, and 15 minute load averages.
+This function always return `[0, 0, 0]` on Windows.
 
 ## os.totalmem()