diff --git a/lib/nconf/stores/memory.js b/lib/nconf/stores/memory.js
index b53ac12c..215953c8 100644
--- a/lib/nconf/stores/memory.js
+++ b/lib/nconf/stores/memory.js
@@ -157,7 +157,7 @@ Memory.prototype.merge = function (key, value) {
   // If the key is not an `Object` or is an `Array`,
   // then simply set it. Merging is for Objects.
   //
-  if (typeof value !== 'object' || Array.isArray(value)) {
+  if (typeof value !== 'object' || Array.isArray(value) || value === null) {
     return this.set(key, value);
   }