diff --git a/lib/schema/string.js b/lib/schema/string.js
index bf1b6d85749..cb8b866c115 100644
--- a/lib/schema/string.js
+++ b/lib/schema/string.js
@@ -242,7 +242,7 @@ SchemaString.prototype.enum = function() {
 
   const vals = this.enumValues;
   this.enumValidator = function(v) {
-    return undefined === v || ~vals.indexOf(v);
+    return null == v || ~vals.indexOf(v);
   };
   this.validators.push({
     validator: this.enumValidator,
diff --git a/test/schema.validation.test.js b/test/schema.validation.test.js
index 22fab457bd1..e467f6ea088 100644
--- a/test/schema.validation.test.js
+++ b/test/schema.validation.test.js
@@ -827,6 +827,19 @@ describe('schema', function() {
       }
     });
 
+    it('should allow null values for enum gh-3044', async function() {
+      const testSchema = new Schema({
+        name: {
+          type: String,
+          enum: ['test']
+        }
+      });
+      const Test = mongoose.model('allow-null' + random(), testSchema);
+      const a = new Test({ name: null });
+      const err = await a.validate().then(() => null, err => err);
+      assert.equal(err, null);
+    });
+
     it('should allow an array of subdocuments with enums (gh-3521)', async function() {
       const coolSchema = new Schema({
         votes: [{