diff --git a/pyup/providers/gitlab.py b/pyup/providers/gitlab.py
index bfb3468..04ee068 100644
--- a/pyup/providers/gitlab.py
+++ b/pyup/providers/gitlab.py
@@ -168,7 +168,7 @@ def close_pull_request(self, bot_repo, user_repo, pull_request, comment, prefix)
         self.delete_branch(user_repo, source_branch, prefix)
 
     def _merge_merge_request(self, mr, config):
-        mr.merge(should_remove_source_branch=config.gitlab.should_remove_source_branch,
+        mr.merge(remove_source_branch=config.gitlab.should_remove_source_branch,
                  merge_when_pipeline_succeeds=True)
 
     def create_pull_request(self, repo, title, body, base_branch, new_branch, pr_label, assignees, config):
@@ -184,7 +184,7 @@ def create_pull_request(self, repo, title, body, base_branch, new_branch, pr_lab
                 'title': title,
                 'description': body,
                 'pr_label': pr_label,
-                'should_remove_source_branch': config.gitlab.should_remove_source_branch
+                'remove_source_branch': config.gitlab.should_remove_source_branch
             })
 
             if config.gitlab.merge_when_pipeline_succeeds:
diff --git a/tests/test_gitlab.py b/tests/test_gitlab.py
index 5aaa2d5..a40bbf3 100644
--- a/tests/test_gitlab.py
+++ b/tests/test_gitlab.py
@@ -211,7 +211,7 @@ def test_merge_pull_request(self):
         config = Config()
         self.provider._merge_merge_request(mr, config)
         mr.merge.assert_called_once_with(merge_when_pipeline_succeeds=True,
-                                         should_remove_source_branch=False)
+                                         remove_source_branch=False)
 
     def test_merge_pull_request_with_remove(self):
         mr = Mock()
@@ -220,7 +220,7 @@ def test_merge_pull_request_with_remove(self):
         config.update_config({'gitlab': {'should_remove_source_branch': True}})
         self.provider._merge_merge_request(mr, config)
         mr.merge.assert_called_once_with(merge_when_pipeline_succeeds=True,
-                                         should_remove_source_branch=True)
+                                         remove_source_branch=True)
 
     def test_create_pull_request_with_exceeding_body(self):
         body = ''.join(["a" for i in range(0, 65536 + 1)])