diff --git a/lib/filters/index.js b/lib/filters/index.js
index bcf5d36..2951c4d 100644
--- a/lib/filters/index.js
+++ b/lib/filters/index.js
@@ -52,7 +52,11 @@ function matchParens(str, openParenIndex) {
     esc = false;
   }
 
-  return str.length - 1;
+  var ndx = str.length - 1;
+  if (str.charAt(ndx) !== ')')
+    throw new Error(str + ' has unbalanced parentheses');
+
+  return ndx;
 }
 
 
@@ -99,6 +103,7 @@ function _buildFilterTree(expr) {
     // out (at least for this recursion level)
     while (expr.length !== 0) {
       endParen = matchParens(expr);
+
       if (endParen == expr.length - 1) {
         tree.children[i] = _buildFilterTree(expr);
         expr = '';
diff --git a/package.json b/package.json
index a2d7eb4..f3351fb 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
   "name": "ldapjs",
   "homepage": "http://ldapjs.org",
   "description": "LDAP client and server APIs",
-  "version": "0.6.1",
+  "version": "0.6.2",
   "repository": {
     "type": "git",
     "url": "git://github.com/mcavage/node-ldapjs.git"
@@ -29,9 +29,9 @@
     "assert-plus": "0.1.2",
     "buffertools": "1.1.0",
     "bunyan": "0.18.2",
-    "dtrace-provider": "0.2.7",
+    "dtrace-provider": "0.2.8",
     "nopt": "2.1.1",
-    "pooling": "0.3.2"
+    "pooling": "0.4.1"
   },
   "devDependencies": {
     "tap": "0.4.0",
diff --git a/test/filters/parse.test.js b/test/filters/parse.test.js
index b09fa42..af2e02f 100644
--- a/test/filters/parse.test.js
+++ b/test/filters/parse.test.js
@@ -139,9 +139,18 @@ test('bogus filter', function (t) {
   t.end();
 });
 
+
 test('bogus filter !=', function (t) {
   t.throws(function () {
     parse('foo!=1');
   });
   t.end();
 });
+
+
+test('mismatched parens', function (t) {
+  t.throws(function () {
+    parse('(&(foo=bar)(!(state=done))');
+  });
+  t.end();
+});