diff --git a/pagure/lib/__init__.py b/pagure/lib/__init__.py
index 6c1975c..9ade9b1 100644
--- a/pagure/lib/__init__.py
+++ b/pagure/lib/__init__.py
@@ -4304,6 +4304,10 @@ def set_project_owner(session, project, user):
     :arg user: a User object representing the new owner of the project.
     :return: None
     '''
+    for contributor in project.users:
+        if user.id == contributor.id:
+            project.users.remove(contributor)
+            break
     project.user = user
     session.add(project)
 
diff --git a/tests/test_pagure_flask_api_project.py b/tests/test_pagure_flask_api_project.py
index 9bb5081..e392c1e 100644
--- a/tests/test_pagure_flask_api_project.py
+++ b/tests/test_pagure_flask_api_project.py
@@ -1242,6 +1242,79 @@ class PagureFlaskApiProjecttests(tests.Modeltests):
             }
             self.assertEqual(data, expected_output)
 
+    def test_api_modify_project_main_admin_retain_access_already_user(self):
+        """ Test the api_modify_project method of the flask api when the
+        request is to change the main_admin of the project and retain_access
+        is true and the user becoming the main_admin already has access. """
+        tests.create_projects(self.session)
+        tests.create_tokens(self.session, project_id=None)
+        tests.create_tokens_acl(self.session, 'aaabbbcccddd', 'modify_project')
+        headers = {'Authorization': 'token aaabbbcccddd'}
+
+        project = pagure.lib._get_project(self.session, 'test')
+        pagure.lib.add_user_to_project(
+            self.session, project,
+            new_user='foo',
+            user='pingou',
+            access='commit'
+        )
+        self.session.commit()
+
+        user = pagure.lib.get_user(self.session, 'pingou')
+        user.cla_done = True
+        with tests.user_set(pagure.APP, user):
+            output = self.app.patch(
+                '/api/0/test', headers=headers,
+                data={'main_admin': 'foo', 'retain_access': True})
+            self.assertEqual(output.status_code, 200)
+            data = json.loads(output.data)
+            data['date_created'] = '1496338274'
+            data['date_modified'] = '1496338274'
+            expected_output = {
+                "access_groups": {
+                    "admin": [],
+                    "commit": [],
+                    "ticket": []
+                },
+                "access_users": {
+                    "admin": [
+                        "pingou"
+                    ],
+                    "commit": [],
+                    "owner": [
+                        "foo"
+                    ],
+                    "ticket": []
+                },
+                "close_status": [
+                    "Invalid",
+                    "Insufficient data",
+                    "Fixed",
+                    "Duplicate"
+                ],
+                "custom_keys": [],
+                "date_created": "1496338274",
+                "date_modified": "1496338274",
+                "description": "test project #1",
+                "fullname": "test",
+                "id": 1,
+                "milestones": {},
+                "name": "test",
+                "namespace": None,
+                "parent": None,
+                "priorities": {},
+                "tags": [],
+                "user": {
+                    "default_email": "foo@bar.com",
+                    "emails": [
+                        "foo@bar.com"
+                    ],
+                    "fullname": "foo bar",
+                    "name": "foo"
+                }
+            }
+            self.assertEqual(data, expected_output)
+
     def test_api_modify_project_main_admin_json(self):
         """ Test the api_modify_project method of the flask api when the
         request is to change the main_admin of the project using JSON. """
diff --git a/tests/test_pagure_flask_ui_app_give_project.py b/tests/test_pagure_flask_ui_app_give_project.py
index 068570c..1b07529 100644
--- a/tests/test_pagure_flask_ui_app_give_project.py
+++ b/tests/test_pagure_flask_ui_app_give_project.py
@@ -260,6 +260,47 @@ class PagureFlaskGiveRepotests(tests.SimplePagureTest):
             self.assertEqual(len(project.users), 1)
             self.assertEqual(project.users[0].user, 'pingou')
 
+    @patch.dict('pagure.APP.config', {'PAGURE_ADMIN_USERS': 'foo'})
+    def test_give_project_already_user(self):
+        """ Test the give_project endpoint when the new main_admin is already
+        a committer on the project. """
+
+        project = pagure.lib._get_project(self.session, 'test')
+        pagure.lib.add_user_to_project(
+            self.session, project,
+            new_user='foo',
+            user='pingou',
+            access='commit'
+        )
+        self.session.commit()
+        user = tests.FakeUser()
+        user.username = 'pingou'
+        with tests.user_set(pagure.APP, user):
+            csrf_token = self.get_csrf()
+
+            self._check_user()
+
+            # All good
+            data = {
+                'user': 'foo',
+                'csrf_token': csrf_token,
+            }
+
+            output = self.app.post(
+                '/test/give', data=data, follow_redirects=True)
+            self.assertEqual(output.status_code, 200)
+            self.assertIn(
+                '</button>\n                      The project has been '
+                'transferred to foo\n',
+                output.data)
+
+            self._check_user('foo')
+            # Make sure that the user giving the project is still an admin
+            project = pagure.get_authorized_project(
+                self.session, project_name='test')
+            self.assertEqual(len(project.users), 1)
+            self.assertEqual(project.users[0].user, 'pingou')
+
 
 if __name__ == '__main__':
     unittest.main(verbosity=2)