diff --git a/rhodecode/api/tests/test_create_pull_request.py b/rhodecode/api/tests/test_create_pull_request.py
--- a/rhodecode/api/tests/test_create_pull_request.py
+++ b/rhodecode/api/tests/test_create_pull_request.py
@@ -113,11 +113,13 @@ class TestCreatePullRequestApi(object):
         data = self._prepare_data(backend)
         reviewers = [
             {'username': TEST_USER_REGULAR_LOGIN,
-             'reasons': ['added manually']},
+             'reasons': ['{} added manually'.format(TEST_USER_REGULAR_LOGIN)]},
             {'username': TEST_USER_ADMIN_LOGIN,
-             'reasons': ['added manually']},
+             'reasons': ['{} added manually'.format(TEST_USER_ADMIN_LOGIN)],
+             'mandatory': True},
         ]
         data['reviewers'] = reviewers
+
         id_, params = build_data(
             self.apikey_regular, 'create_pull_request', **data)
         response = api_call(self.app, params)
@@ -128,12 +130,24 @@ class TestCreatePullRequestApi(object):
         assert result['result']['msg'] == expected_message
         pull_request_id = result['result']['pull_request_id']
         pull_request = PullRequestModel().get(pull_request_id)
-        actual_reviewers = [
-            {'username': r.user.username,
-             'reasons': ['added manually'],
-             } for r in pull_request.reviewers
-        ]
-        assert sorted(actual_reviewers) == sorted(reviewers)
+
+        actual_reviewers = []
+        for rev in pull_request.reviewers:
+            entry = {
+                'username': rev.user.username,
+                'reasons': rev.reasons,
+             }
+            if rev.mandatory:
+                entry['mandatory'] = rev.mandatory
+            actual_reviewers.append(entry)
+
+        # default reviewer will be added who is an owner of the repo
+        reviewers.append(
+            {'username': pull_request.author.username,
+             'reasons': [u'Default reviewer', u'Repository owner']},
+        )
+        assert sorted(actual_reviewers, key=lambda e: e['username']) \
+               == sorted(reviewers, key=lambda e: e['username'])
 
     @pytest.mark.backends("git", "hg")
     def test_create_with_reviewers_specified_by_ids(
@@ -159,12 +173,23 @@ class TestCreatePullRequestApi(object):
         assert result['result']['msg'] == expected_message
         pull_request_id = result['result']['pull_request_id']
         pull_request = PullRequestModel().get(pull_request_id)
-        actual_reviewers = [
-            {'username': r.user.user_id,
-             'reasons': ['added manually'],
-             } for r in pull_request.reviewers
-        ]
-        assert sorted(actual_reviewers) == sorted(reviewers)
+
+        actual_reviewers = []
+        for rev in pull_request.reviewers:
+            entry = {
+                'username': rev.user.user_id,
+                'reasons': rev.reasons,
+             }
+            if rev.mandatory:
+                entry['mandatory'] = rev.mandatory
+            actual_reviewers.append(entry)
+        # default reviewer will be added who is an owner of the repo
+        reviewers.append(
+            {'username': pull_request.author.user_id,
+             'reasons': [u'Default reviewer', u'Repository owner']},
+        )
+        assert sorted(actual_reviewers, key=lambda e: e['username']) \
+               == sorted(reviewers, key=lambda e: e['username'])
 
     @pytest.mark.backends("git", "hg")
     def test_create_fails_when_the_reviewer_is_not_found(self, backend):
@@ -271,9 +296,10 @@ class TestCreatePullRequestApi(object):
     def test_create_fails_when_no_permissions(self, backend):
         data = self._prepare_data(backend)
         RepoModel().revoke_user_permission(
-            self.source.repo_name, User.DEFAULT_USER)
+            self.source.repo_name, self.test_user)
         RepoModel().revoke_user_permission(
-            self.source.repo_name, self.test_user)
+            self.source.repo_name, User.DEFAULT_USER)
+
         id_, params = build_data(
             self.apikey_regular, 'create_pull_request', **data)
         response = api_call(self.app, params)
diff --git a/rhodecode/api/views/pull_request_api.py b/rhodecode/api/views/pull_request_api.py
--- a/rhodecode/api/views/pull_request_api.py
+++ b/rhodecode/api/views/pull_request_api.py
@@ -641,6 +641,7 @@ def create_pull_request(
 
     reviewer_objects = Optional.extract(reviewers) or []
 
+    # serialize and validate passed in given reviewers
     if reviewer_objects:
         schema = ReviewerListSchema()
         try:
@@ -653,20 +654,19 @@ def create_pull_request(
             user = get_user_or_error(reviewer_object['username'])
             reviewer_object['user_id'] = user.user_id
 
-    get_default_reviewers_data, get_validated_reviewers = \
+    get_default_reviewers_data, validate_default_reviewers = \
         PullRequestModel().get_reviewer_functions()
 
+    # recalculate reviewers logic, to make sure we can validate this
     reviewer_rules = get_default_reviewers_data(
         apiuser.get_instance(), source_db_repo,
         source_commit, target_db_repo, target_commit)
 
-    # specified rules are later re-validated, thus we can assume users will
-    # eventually provide those that meet the reviewer criteria.
-    if not reviewer_objects:
-        reviewer_objects = reviewer_rules['reviewers']
+    # now MERGE our given with the calculated
+    reviewer_objects = reviewer_rules['reviewers'] + reviewer_objects
 
     try:
-        reviewers = get_validated_reviewers(
+        reviewers = validate_default_reviewers(
             reviewer_objects, reviewer_rules)
     except ValueError as e:
         raise JSONRPCError('Reviewers Validation: {}'.format(e))
diff --git a/rhodecode/apps/repository/views/repo_pull_requests.py b/rhodecode/apps/repository/views/repo_pull_requests.py
--- a/rhodecode/apps/repository/views/repo_pull_requests.py
+++ b/rhodecode/apps/repository/views/repo_pull_requests.py
@@ -881,7 +881,8 @@ class RepoPullRequestsView(RepoAppView, 
             source_commit, target_db_repo, target_commit)
 
         given_reviewers = _form['review_members']
-        reviewers = validate_default_reviewers(given_reviewers, reviewer_rules)
+        reviewers = validate_default_reviewers(
+            given_reviewers, reviewer_rules)
 
         pullrequest_title = _form['pullrequest_title']
         title_source_ref = source_ref.split(':', 2)[1]