diff --git a/lib/nconf/stores/argv.js b/lib/nconf/stores/argv.js
index 04e1fd4..666c853 100644
--- a/lib/nconf/stores/argv.js
+++ b/lib/nconf/stores/argv.js
@@ -58,7 +58,9 @@ Argv.prototype.loadArgv = function () {
 
   this.readOnly = false;
   Object.keys(argv).forEach(function (key) {
-    self.set(key, argv[key]);
+    if (typeof argv[key] !== 'undefined') {
+      self.set(key, argv[key]);
+    }
   });
 
   this.showHelp = yargs.showHelp