diff --git a/lib/auth.js b/lib/auth.js
index b7ed4caf2..ff15610dd 100644
--- a/lib/auth.js
+++ b/lib/auth.js
@@ -71,9 +71,11 @@ digest.generate = function(header, user, pass, method, path) {
     cnonce = md5(Math.random().toString(36)).substr(0, 8);
     nc     = digest.update_nc(nc);
     resp   = resp.concat(nc, cnonce);
+    resp   = resp.concat(challenge.qop, ha2);
+  } else {
+    resp   = resp.concat(ha2);
   }
 
-  resp = resp.concat(challenge.qop, ha2);
 
   var params = {
     uri      : path,
diff --git a/test/auth_digest_spec.js b/test/auth_digest_spec.js
new file mode 100644
index 000000000..a96b852d9
--- /dev/null
+++ b/test/auth_digest_spec.js
@@ -0,0 +1,116 @@
+var needle  = require('../'),
+    auth = require('../lib/auth'),
+    sinon   = require('sinon'),
+    should  = require('should'),
+    http    = require('http'),
+    helpers = require('./helpers');
+
+var createHash = require('crypto').createHash;
+
+function md5(string) {
+  return createHash('md5').update(string).digest('hex');
+}
+
+function parse_header(header) {
+  var challenge = {},
+      matches   = header.match(/([a-z0-9_-]+)="?([a-z0-9=\/\.@\s-]+)"?/gi);
+
+  for (var i = 0, l = matches.length; i < l; i++) {
+    var parts = matches[i].split('='),
+        key   = parts.shift(),
+        val   = parts.join('=').replace(/^"/, '').replace(/"$/, '');
+
+    challenge[key] = val;
+  }
+
+  return challenge;
+}
+
+describe('auth_digest', function() {
+  describe('With qop (RFC 2617)', function() {
+    it('should generate a proper header', function() {
+      // from https://tools.ietf.org/html/rfc2617
+      var performDigest = function() {
+        var header = 'Digest realm="testrealm@host.com", qop="auth,auth-int", nonce="dcd98b7102dd2f0e8b11d0f600bfb0c093", opaque="5ccc069c403ebaf9f0171e9517f40e41"';
+        var user = 'Mufasa';
+        var pass = 'Circle Of Life';
+        var method = 'get';
+        var path = '/dir/index.html';
+
+        var updatedHeader = auth.digest(header, user, pass, method, path);
+        var parsedUpdatedHeader = parse_header(updatedHeader);
+
+        var ha1 = md5(user + ':' + parsedUpdatedHeader.realm + ':' + pass);
+        var ha2 = md5(method.toUpperCase() + ':' + path);
+        var expectedResponse = md5([
+          ha1,
+          parsedUpdatedHeader.nonce,
+          parsedUpdatedHeader.nc,
+          parsedUpdatedHeader.cnonce,
+          parsedUpdatedHeader.qop,
+          ha2
+        ].join(':'));
+
+        return {
+          header: updatedHeader,
+          parsed: parsedUpdatedHeader,
+          expectedResponse: expectedResponse,
+        }
+      }
+
+      const result = performDigest();
+
+      (result.header).should
+        .match(/qop="auth"/)
+        .match(/uri="\/dir\/index.html"/)
+        .match(/opaque="5ccc069c403ebaf9f0171e9517f40e41"/)
+        .match(/realm="testrealm@host\.com"/)
+        .match(/response=/)
+        .match(/nc=/)
+        .match(/nonce=/)
+        .match(/cnonce=/);
+
+      (result.parsed.response).should.be.eql(result.expectedResponse);
+    });
+  });
+
+  describe('Without qop (RFC 2617)', function() {
+    it('should generate a proper header', function() {
+      // from https://tools.ietf.org/html/rfc2069
+      var performDigest = function() {
+        var header = 'Digest realm="testrealm@host.com", nonce="dcd98b7102dd2f0e8b11d0f600bfb0c093", opaque="5ccc069c403ebaf9f0171e9517f40e41"';
+        var user = 'Mufasa';
+        var pass = 'Circle Of Life';
+        var method = 'get';
+        var path = '/dir/index.html';
+
+        var updatedHeader = auth.digest(header, user, pass, method, path);
+        var parsedUpdatedHeader = parse_header(updatedHeader);
+
+        var ha1 = md5(user + ':' + parsedUpdatedHeader.realm + ':' + pass);
+        var ha2 = md5(method.toUpperCase() + ':' + path);
+        var expectedResponse = md5([ha1, parsedUpdatedHeader.nonce, ha2].join(':'));
+
+        return {
+          header: updatedHeader,
+          parsed: parsedUpdatedHeader,
+          expectedResponse: expectedResponse,
+        }
+      }
+
+      const result = performDigest();
+
+      (result.header).should
+        .not.match(/qop=/)
+        .match(/uri="\/dir\/index.html"/)
+        .match(/opaque="5ccc069c403ebaf9f0171e9517f40e41"/)
+        .match(/realm="testrealm@host\.com"/)
+        .match(/response=/)
+        .not.match(/nc=/)
+        .match(/nonce=/)
+        .not.match(/cnonce=/);
+
+      (result.parsed.response).should.be.eql(result.expectedResponse);
+    });
+  });
+})