diff --git a/lib/UrlClassifier.js b/lib/UrlClassifier.js
index 5da194f..17d25b5 100644
--- a/lib/UrlClassifier.js
+++ b/lib/UrlClassifier.js
@@ -79,30 +79,33 @@ UrlClassifier.prototype = {
       return this._deferred.promise;
     }
 
-    this._deferred = Promise.defer();
+    let deferred = this._deferred = Promise.defer();
     this._results = {};
-
-    // submit url+title to workers
-    let url = url;
-    let title = title || "";
-    let uri = NetUtil.newURI(url);
-    let host = getPlacesHostForURI(uri);
-    let message = {};
-    message.message = "getInterestsForDocument";
-    message.url = url;
-    message.title = title;
-    message.host = host;
-    message.path = uri["path"];
-    message.tld = getBaseDomain(host);
-    message.metaData = {};
-    message.language = "en";
-    message.messageId = "classifyUrl";
-    this._expectedResponses = this._workers.length;
-    this._workers.forEach(worker => {
-      this._callMatchingWorker(worker, message);
-    });
-
-    return this._deferred.promise;
+    try {
+      // submit url+title to workers
+      let title = title || "";
+      let uri = NetUtil.newURI(url);
+      let host = getPlacesHostForURI(uri);
+      let message = {};
+      message.message = "getInterestsForDocument";
+      message.url = url;
+      message.title = title;
+      message.host = host;
+      message.path = uri["path"];
+      message.tld = getBaseDomain(host);
+      message.metaData = {};
+      message.language = "en";
+      message.messageId = "classifyUrl";
+      this._expectedResponses = this._workers.length;
+      this._workers.forEach(worker => {
+        this._callMatchingWorker(worker, message);
+      });
+    }
+    catch (e) {
+      this._deferred = null;
+      deferred.reject(e);
+    }
+    return deferred.promise;
   },
 
 }
diff --git a/test/test-UrlClassifier.js b/test/test-UrlClassifier.js
index 481285b..d355947 100644
--- a/test/test-UrlClassifier.js
+++ b/test/test-UrlClassifier.js
@@ -33,6 +33,13 @@ exports["test url classifier"] = function test_UrlClassifier(assert, done) {
            {"type":"combined","interests":["Autos"]},
            {"type":"keywords","interests":[]}
           ]);
+    // test for an error 
+    yield urlClassifier.classifyPage("not a url").then(result => {
+      assert.ok(false);
+    },
+    error => {
+      assert.ok(true);
+    });
 
   }).then(done);
 }