diff --git a/src/bloodhound/persistent_storage.js b/src/bloodhound/persistent_storage.js
index 4a85acbd..07c62029 100644
--- a/src/bloodhound/persistent_storage.js
+++ b/src/bloodhound/persistent_storage.js
@@ -24,7 +24,7 @@ var PersistentStorage = (function() {
   function PersistentStorage(namespace) {
     this.prefix = ['__', namespace, '__'].join('');
     this.ttlKey = '__ttl__';
-    this.keyMatcher = new RegExp('^' + this.prefix);
+    this.keyMatcher = new RegExp('^' + _.escapeRegExChars(this.prefix));
   }
 
   // instance methods
diff --git a/test/persistent_storage_spec.js b/test/persistent_storage_spec.js
index 495f8eff..6c8dc43c 100644
--- a/test/persistent_storage_spec.js
+++ b/test/persistent_storage_spec.js
@@ -81,6 +81,16 @@ describe('PersistentStorage', function() {
   });
 
   describe('#clear', function() {
+    it('should work with namespaces that contain regex characters', function() {
+      engine = new PersistentStorage('ns?()');
+      engine.set('key1', 'val1');
+      engine.set('key2', 'val2');
+      engine.clear();
+
+      expect(engine.get('key1')).toEqual(undefined);
+      expect(engine.get('key2')).toEqual(undefined);
+    });
+
     it('should remove all keys that exist in namespace of engine', function() {
       engine.set('key1', 'val1');
       engine.set('key2', 'val2');