diff --git a/doc/source/specification/murano-api.rst b/doc/source/specification/murano-api.rst
index ed627bfc8..74a7c5db2 100644
--- a/doc/source/specification/murano-api.rst
+++ b/doc/source/specification/murano-api.rst
@@ -204,6 +204,21 @@ Update Environment
         "version": 0
     }
 
++----------------+-----------------------------------------------------------+
+| Code           | Description                                               |
++================+===========================================================+
+| 200            | Edited environment                                        |
++----------------+-----------------------------------------------------------+
+| 400            | Environment name must contain only alphanumeric or '_-.'  |
+|                | characters, must start with alpha                         |
++----------------+-----------------------------------------------------------+
+| 401            | User is not authorized to access environment              |
++----------------+-----------------------------------------------------------+
+| 404            | Environment not found                                     |
++----------------+-----------------------------------------------------------+
+| 409            | Environment with specified name already exists            |
++----------------+-----------------------------------------------------------+
+
 Get Environment Details
 -----------------------
 
diff --git a/murano/api/v1/environments.py b/murano/api/v1/environments.py
index 8818cbde8..b63824b7e 100644
--- a/murano/api/v1/environments.py
+++ b/murano/api/v1/environments.py
@@ -126,8 +126,13 @@ class Controller(object):
 
         LOG.debug('ENV NAME: {0}>'.format(body['name']))
         if VALID_NAME_REGEX.match(str(body['name'])):
-            environment.update(body)
-            environment.save(session)
+            try:
+                environment.update(body)
+                environment.save(session)
+            except db_exc.DBDuplicateEntry:
+                msg = _('Environment with specified name already exists')
+                LOG.exception(msg)
+                raise exc.HTTPConflict(explanation=msg)
         else:
             msg = _('Environment name must contain only alphanumeric '
                     'or "_-." characters, must start with alpha')
diff --git a/murano/tests/unit/api/v1/test_environments.py b/murano/tests/unit/api/v1/test_environments.py
index 5aad6a8e8..07facb1c6 100644
--- a/murano/tests/unit/api/v1/test_environments.py
+++ b/murano/tests/unit/api/v1/test_environments.py
@@ -196,6 +196,63 @@ class TestEnvironmentApi(tb.ControllerTest, tb.MuranoApiTestCase):
 
         self.assertEqual(expected, json.loads(result.body))
 
+    def test_update_environment_with_existing_name(self):
+        self._set_policy_rules(
+            {'update_environment': '@'}
+        )
+
+        fake_now = timeutils.utcnow()
+        timeutils.utcnow.override_time = fake_now
+
+        expected = dict(
+            id='111',
+            name='env1',
+            version=0,
+            networking={},
+            created=fake_now,
+            updated=fake_now,
+            tenant_id=self.tenant,
+            description={
+                'Objects': {
+                    '?': {'id': '111'}
+                },
+                'Attributes': []
+            }
+        )
+        e = models.Environment(**expected)
+        test_utils.save_models(e)
+
+        fake_now = timeutils.utcnow()
+        timeutils.utcnow.override_time = fake_now
+
+        expected = dict(
+            id='222',
+            name='env2',
+            version=0,
+            networking={},
+            created=fake_now,
+            updated=fake_now,
+            tenant_id=self.tenant,
+            description={
+                'Objects': {
+                    '?': {'id': '222'}
+                },
+                'Attributes': []
+            }
+        )
+        e = models.Environment(**expected)
+        test_utils.save_models(e)
+
+        self.expect_policy_check('update_environment',
+                                 {'environment_id': '111'})
+
+        body = {
+            'name': 'env2'
+        }
+        req = self._put('/environments/111', json.dumps(body))
+        result = req.get_response(self.api)
+        self.assertEqual(409, result.status_code)
+
     def test_delete_environment(self):
         """Test that environment deletion results in the correct rpc call."""
         self._set_policy_rules(