diff --git a/checks.d/marathon.py b/checks.d/marathon.py
index 0542b4ffa5..f7ec117c7a 100644
--- a/checks.d/marathon.py
+++ b/checks.d/marathon.py
@@ -1,3 +1,6 @@
+# stdlib
+from urlparse import urljoin
+
 # project
 from checks import AgentCheck
 
@@ -31,7 +34,7 @@ def check(self, instance):
         default_timeout = self.init_config.get('default_timeout', self.DEFAULT_TIMEOUT)
         timeout = float(instance.get('timeout', default_timeout))
 
-        response = self.get_json(url + "/v2/apps", timeout)
+        response = self.get_json(urljoin(url, "/v2/apps"), timeout)
         if response is not None:
             self.gauge('marathon.apps', len(response['apps']), tags=instance_tags)
             for app in response['apps']:
@@ -39,7 +42,10 @@ def check(self, instance):
                 for attr in self.APP_METRICS:
                     if attr in app:
                         self.gauge('marathon.' + attr, app[attr], tags=tags)
-                versions_reply = self.get_json(url + "/v2/apps/" + app['id'] + "/versions", timeout)
+
+                query_url = urljoin(url, "/v2/apps/{0}/versions".format(app['id']))
+                versions_reply = self.get_json(query_url, timeout)
+
                 if versions_reply is not None:
                     self.gauge('marathon.versions', len(versions_reply['versions']), tags=tags)