diff --git a/newrelic_api/servers.py b/newrelic_api/servers.py
index <HASH>..<HASH> 100644
--- a/newrelic_api/servers.py
+++ b/newrelic_api/servers.py
@@ -54,7 +54,9 @@ class Servers(Resource):
             }
 
         """
-        label_param = ';'.join(['{}:{}'.format(label, value) for label, value in filter_labels.items()])
+        if filter_labels:
+            label_param = ';'.join(['{}:{}'.format(label, value) for label, value in filter_labels.items()])
+
         filters = [
             'filter[name]={0}'.format(filter_name) if filter_name else None,
             'filter[ids]={0}'.format(','.join([str(app_id) for app_id in filter_ids])) if filter_ids else None,
Fix code if `filter_labels` is `None`