diff --git a/lib/mock/index.js b/lib/mock/index.js
index d6e3931..a0fe48d 100644
--- a/lib/mock/index.js
+++ b/lib/mock/index.js
@@ -51,52 +51,58 @@ function mock(context, router, dataStore) {
    * Determines the best Response object for this request and sets `res.swagger` to a {@link SemanticRequest} object.
    * Also sets `res.statusCode` if it isn't already set.
    */
-  function mockResponse(req, res, next) {
-    if (util.isSwaggerRequest(req) && !isDisabled()) {
-      var response;
-
-      // Is there already a statusCode? (perhaps set by third-party middleware)
-      if (res.statusCode && req.swagger.operation.responses[res.statusCode]) {
-        util.debug('Using %s response for %s %s', res.statusCode, req.method, req.path);
-        response = req.swagger.operation.responses[res.statusCode];
-      }
-      else {
-        // Use the first response with a 2XX or 3XX code (or "default")
-        var responses = util.getResponsesBetween(req.swagger.operation, 200, 399);
-        if (responses.length > 0) {
-          response = responses[0].api;
-
-          // Set the response status code
-          if (_.isNumber(responses[0].code)) {
-            util.debug('Using %s response for %s %s', responses[0].code, req.method, req.path);
-            res.status(responses[0].code);
+  function mockResponse (req, res, next) {
+    if (!util.isSwaggerRequest(req) ||
+      isDisabled() ||
+      _.isEmpty(req.swagger.operation.responses)
+    ) {
+      next();
+      return;
+    }
+
+    var response;
+
+    // Is there already a statusCode? (perhaps set by third-party middleware)
+    if (res.statusCode && req.swagger.operation.responses[res.statusCode]) {
+      util.debug('Using %s response for %s %s', res.statusCode, req.method, req.path);
+      response = req.swagger.operation.responses[res.statusCode];
+    }
+    else {
+      // Use the first response with a 2XX or 3XX code (or "default")
+      var responses = util.getResponsesBetween(req.swagger.operation, 200, 399);
+      if (responses.length > 0) {
+        response = responses[0].api;
+
+        // Set the response status code
+        if (_.isNumber(responses[0].code)) {
+          util.debug('Using %s response for %s %s', responses[0].code, req.method, req.path);
+          res.status(responses[0].code);
+        }
+        else {
+          if (req.method === 'POST' || req.method === 'PUT') {
+            res.status(201);
+          }
+          else if (req.method === 'DELETE' && !responses[0].api.schema) {
+            res.status(204);
           }
           else {
-            if (req.method === 'POST' || req.method === 'PUT') {
-              res.status(201);
-            }
-            else if (req.method === 'DELETE' && !responses[0].api.schema) {
-              res.status(204);
-            }
-            else {
-              res.status(200);
-            }
-            util.debug('Using %s (%d) response for %s %s', responses[0].code, res.statusCode, req.method, req.path);
+            res.status(200);
           }
-        }
-        else {
-          // There is no response with a 2XX or 3XX code, so just use the first one
-          var keys = Object.keys(req.swagger.operation.responses);
-          util.debug('Using %s response for %s %s', keys[0], req.method, req.path);
-          response = req.swagger.operation.responses[keys[0]];
-          res.status(parseInt(keys[0]));
+          util.debug('Using %s (%d) response for %s %s', responses[0].code, res.statusCode, req.method, req.path);
         }
       }
-
-      // The rest of the Mock middleware will use this ResponseMetadata object
-      res.swagger = new SemanticResponse(response, req.swagger.path);
+      else {
+        // There is no response with a 2XX or 3XX code, so just use the first one
+        var keys = Object.keys(req.swagger.operation.responses);
+        util.debug('Using %s response for %s %s', keys[0], req.method, req.path);
+        response = req.swagger.operation.responses[keys[0]];
+        res.status(parseInt(keys[0]));
+      }
     }
 
+    // The rest of the Mock middleware will use this ResponseMetadata object
+    res.swagger = new SemanticResponse(response, req.swagger.path);
+
     next();
   }