diff --git a/src/urlMatcherFactory.js b/src/urlMatcherFactory.js
index fa4edf16d..67da94120 100644
--- a/src/urlMatcherFactory.js
+++ b/src/urlMatcherFactory.js
@@ -301,7 +301,7 @@ UrlMatcher.prototype.format = function (values) {
   if (!values) return segments.join('').replace('//', '/');
 
   var nPath = segments.length - 1, nTotal = params.length,
-    result = segments[0], i, search, value, param, cfg;
+    result = segments[0], i, search, value, param, cfg, array;
 
   if (!this.validates(values)) return null;
 
@@ -317,8 +317,14 @@ UrlMatcher.prototype.format = function (values) {
 
   for (/**/; i < nTotal; i++) {
     param = params[i];
-    if (values[param] == null) continue;
-    result += (search ? '&' : '?') + param + '=' + encodeURIComponent(values[param]);
+    value = values[param];
+    if (value == null) continue;
+    array = isArray(value);
+
+    if (array) {
+      value = value.map(encodeURIComponent).join('&' + param + '=');
+    }
+    result += (search ? '&' : '?') + param + '=' + (array ? value : encodeURIComponent(value));
     search = true;
   }
   return result;
diff --git a/test/urlMatcherFactorySpec.js b/test/urlMatcherFactorySpec.js
index 1926c491e..0b253a123 100644
--- a/test/urlMatcherFactorySpec.js
+++ b/test/urlMatcherFactorySpec.js
@@ -55,13 +55,13 @@ describe("UrlMatcher", function () {
 
   it("should parse parameter placeholders", function () {
     var matcher = new UrlMatcher('/users/:id/details/{type}/{repeat:[0-9]+}?from&to');
-    var params = matcher.parameters();
-    expect(params.length).toBe(5);
-    expect(params).toContain('id');
-    expect(params).toContain('type');
-    expect(params).toContain('repeat');
-    expect(params).toContain('from');
-    expect(params).toContain('to');
+    expect(matcher.parameters()).toEqual(['id', 'type', 'repeat', 'from', 'to']);
+  });
+
+  it("should encode and decode duplicate query string values as array", function () {
+    var matcher = new UrlMatcher('/?foo'), array = { foo: ["bar", "baz"] };
+    expect(matcher.exec('/', array)).toEqual(array);
+    expect(matcher.format(array)).toBe('/?foo=bar&foo=baz');
   });
 
   describe("snake-case parameters", function() {