diff --git a/jenkins/__init__.py b/jenkins/__init__.py
index 4aea85b..dd98dcb 100644
--- a/jenkins/__init__.py
+++ b/jenkins/__init__.py
@@ -128,6 +128,11 @@ class JenkinsException(Exception):
     pass
 
 
+class NotFoundException(JenkinsException):
+    '''A special exception to call out the case of receiving a 404.'''
+    pass
+
+
 def auth_headers(username, password):
     '''Simple implementation of HTTP Basic Authentication.
 
@@ -169,13 +174,14 @@ class Jenkins(object):
     def maybe_add_crumb(self, req):
         # We don't know yet whether we need a crumb
         if self.crumb is None:
-            response = self.jenkins_open(Request(
-                self.server + CRUMB_URL), add_crumb=False)
-            if response:
-                self.crumb = json.loads(response.decode('utf-8'))
-            else:
+            try:
+                response = self.jenkins_open(Request(
+                    self.server + CRUMB_URL), add_crumb=False)
+            except NotFoundException:
                 # Don't need crumbs
                 self.crumb = False
+            else:
+                self.crumb = json.loads(response.decode('utf-8'))
         if self.crumb:
             req.add_header(self.crumb['crumbRequestField'], self.crumb['crumb'])
 
@@ -209,17 +215,19 @@ class Jenkins(object):
         :param name: Job name, ``str``
         :returns: Name of job or None
         '''
-        response = self.jenkins_open(
-            Request(self.server + JOB_NAME % self._get_encoded_params(locals())))
-        if response:
+        try:
+            response = self.jenkins_open(
+                Request(self.server + JOB_NAME %
+                        self._get_encoded_params(locals())))
+        except NotFoundException:
+            return None
+        else:
             actual = json.loads(response)['name']
             if actual != name:
                 raise JenkinsException(
                     'Jenkins returned an unexpected job name %s '
                     '(expected: %s)' % (actual, name))
             return actual
-        else:
-            return None
 
     def debug_job_info(self, job_name):
         '''Print out job info in more readable format.'''
@@ -250,6 +258,8 @@ class Jenkins(object):
                     'Possibly authentication failed [%s]: %s' % (
                         e.code, e.msg)
                 )
+            elif e.code == 404:
+                raise NotFoundException('Requested item could not be found')
             # right now I'm getting 302 infinites on a successful delete
 
     def get_build_info(self, name, number, depth=0):
@@ -307,9 +317,14 @@ class Jenkins(object):
         '''
         # Jenkins seems to always return a 404 when using this REST endpoint
         # https://issues.jenkins-ci.org/browse/JENKINS-21311
-        self.jenkins_open(
-            Request(self.server + CANCEL_QUEUE % locals(), '',
-                    headers={'Referer': self.server}))
+        try:
+            self.jenkins_open(
+                Request(self.server + CANCEL_QUEUE % locals(), '',
+                        headers={'Referer': self.server}))
+        except NotFoundException:
+            # Exception is expected; cancel_queue() is a best-effort
+            # mechanism, so ignore it
+            pass
 
     def get_info(self):
         """Get information on this Master.
diff --git a/tests/test_jenkins.py b/tests/test_jenkins.py
index afe6f53..e7aec31 100644
--- a/tests/test_jenkins.py
+++ b/tests/test_jenkins.py
@@ -88,7 +88,7 @@ class JenkinsTest(unittest.TestCase):
 
     @patch('jenkins.urlopen')
     def test_maybe_add_crumb(self, jenkins_mock):
-        jenkins_mock.return_value = get_mock_urlopen_return_value()
+        jenkins_mock.side_effect = jenkins.NotFoundException()
         j = jenkins.Jenkins('http://example.com/', 'test', 'test')
         request = jenkins.Request('http://example.com/job/TestJob')
 
@@ -162,11 +162,29 @@ class JenkinsTest(unittest.TestCase):
             jenkins_mock.call_args[0][0].get_full_url(),
             'http://example.com/job/TestJob')
 
+    @patch('jenkins.urlopen')
+    def test_jenkins_open__404(self, jenkins_mock):
+        jenkins_mock.side_effect = jenkins.HTTPError(
+            'http://example.com/job/TestJob',
+            code=404,
+            msg="basic auth failed",
+            hdrs=[],
+            fp=None)
+        j = jenkins.Jenkins('http://example.com/', 'test', 'test')
+        request = jenkins.Request('http://example.com/job/TestJob')
+
+        with self.assertRaises(jenkins.NotFoundException) as context_manager:
+            j.jenkins_open(request, add_crumb=False)
+        self.assertEqual(
+            str(context_manager.exception),
+            'Requested item could not be found')
+        self.assertEqual(
+            jenkins_mock.call_args[0][0].get_full_url(),
+            'http://example.com/job/TestJob')
+
     @patch.object(jenkins.Jenkins, 'jenkins_open')
     def test_assert_job_exists__job_missing(self, jenkins_mock):
-        jenkins_mock.side_effect = [
-            None,
-        ]
+        jenkins_mock.side_effect = jenkins.NotFoundException()
         j = jenkins.Jenkins('http://example.com/', 'test', 'test')
 
         with self.assertRaises(jenkins.JenkinsException) as context_manager:
@@ -191,7 +209,7 @@ class JenkinsTest(unittest.TestCase):
                 <description>Foo</description>
             </matrix-project>"""
         jenkins_mock.side_effect = [
-            None,
+            jenkins.NotFoundException(),
             None,
             json.dumps({'name': 'Test Job'}),
         ]
@@ -233,9 +251,9 @@ class JenkinsTest(unittest.TestCase):
                 <description>Foo</description>
             </matrix-project>"""
         jenkins_mock.side_effect = [
+            jenkins.NotFoundException(),
             None,
-            None,
-            None,
+            jenkins.NotFoundException(),
         ]
         j = jenkins.Jenkins('http://example.com/', 'test', 'test')
 
@@ -317,7 +335,7 @@ class JenkinsTest(unittest.TestCase):
 
     @patch.object(jenkins.Jenkins, 'jenkins_open')
     def test_build_job__job_doesnt_exist(self, jenkins_mock):
-        jenkins_mock.side_effect = [None]
+        jenkins_mock.side_effect = jenkins.NotFoundException()
         j = jenkins.Jenkins('http://example.com/', 'test', 'test')
 
         with self.assertRaises(jenkins.JenkinsException) as context_manager:
@@ -833,8 +851,7 @@ class JenkinsTest(unittest.TestCase):
         jenkins_mock.side_effect = [
             json.dumps({'name': 'TestJob'}),
             None,
-            None,
-            None,
+            jenkins.NotFoundException(),
         ]
         j = jenkins.Jenkins('http://example.com/', 'test', 'test')
 
@@ -870,8 +887,7 @@ class JenkinsTest(unittest.TestCase):
         jenkins_mock.side_effect = [
             json.dumps({'name': 'TestJob'}),
             None,
-            None,
-            None,
+            jenkins.NotFoundException(),
         ]
         j = jenkins.Jenkins('http://example.com/', 'test', 'test')
 
@@ -889,8 +905,7 @@ class JenkinsTest(unittest.TestCase):
         jenkins_mock.side_effect = [
             json.dumps({'name': 'Test Job'}),
             None,
-            None,
-            None,
+            jenkins.NotFoundException(),
         ]
         j = jenkins.Jenkins('http://example.com/', 'test', 'test')
 
@@ -899,7 +914,6 @@ class JenkinsTest(unittest.TestCase):
         self.assertEqual(
             jenkins_mock.call_args_list[1][0][0].get_full_url(),
             'http://example.com/job/Test%20Job/doDelete')
-        self.assertFalse(j.job_exists('Test Job'))
 
     @patch.object(jenkins.Jenkins, 'jenkins_open')
     def test_delete_job__delete_failed(self, jenkins_mock):
@@ -967,7 +981,7 @@ class JenkinsTest(unittest.TestCase):
 
     @patch.object(jenkins.Jenkins, 'jenkins_open')
     def test_get_job_name__None(self, jenkins_mock):
-        jenkins_mock.return_value = None
+        jenkins_mock.side_effect = jenkins.NotFoundException()
         j = jenkins.Jenkins('http://example.com/', 'test', 'test')
 
         job_name = j.get_job_name(u'TestJob')
@@ -1005,6 +1019,19 @@ class JenkinsTest(unittest.TestCase):
             jenkins_mock.call_args[0][0].get_full_url(),
             u'http://example.com/queue/cancelItem?id=52')
 
+    @patch.object(jenkins.Jenkins, 'jenkins_open',
+                  side_effect=jenkins.NotFoundException('not found'))
+    def test_cancel_queue__notfound(self, jenkins_mock):
+        job_name_to_return = {u'name': 'TestJob'}
+        jenkins_mock.return_value = json.dumps(job_name_to_return)
+        j = jenkins.Jenkins('http://example.com/', 'test', 'test')
+
+        j.cancel_queue(52)
+
+        self.assertEqual(
+            jenkins_mock.call_args[0][0].get_full_url(),
+            u'http://example.com/queue/cancelItem?id=52')
+
     @patch.object(jenkins.Jenkins, 'jenkins_open')
     def test_get_node_info(self, jenkins_mock):
         node_info = {