diff --git a/optimizely/decision_service.py b/optimizely/decision_service.py
index 28275ef..e5fe638 100644
--- a/optimizely/decision_service.py
+++ b/optimizely/decision_service.py
@@ -457,7 +457,8 @@ def get_variation(
             }
 
         # Check to see if user has a decision available for the given experiment
-        if user_profile_tracker is not None and not ignore_user_profile:
+        # Exclude CMAB experiments from UPS sticky bucketing
+        if user_profile_tracker is not None and not ignore_user_profile and not experiment.cmab:
             variation = self.get_stored_variation(project_config, experiment, user_profile_tracker.get_user_profile())
             if variation:
                 message = f'Returning previously activated variation ID "{variation}" of experiment ' \
@@ -472,6 +473,10 @@ def get_variation(
                 }
             else:
                 self.logger.warning('User profile has invalid format.')
+        elif experiment.cmab:
+            message = 'Skipped user profile lookup for CMAB experiment.'
+            self.logger.debug(message)
+            decide_reasons.append(message)
 
         # Check audience conditions
         audience_conditions = experiment.get_audience_conditions_or_ids()
@@ -529,11 +534,16 @@ def get_variation(
             self.logger.info(message)
             decide_reasons.append(message)
             # Store this new decision and return the variation for the user
-            if user_profile_tracker is not None and not ignore_user_profile:
+            # Exclude CMAB experiments from UPS sticky bucketing
+            if user_profile_tracker is not None and not ignore_user_profile and not experiment.cmab:
                 try:
                     user_profile_tracker.update_user_profile(experiment, variation)
                 except:
                     self.logger.exception(f'Unable to save user profile for user "{user_id}".')
+            elif experiment.cmab:
+                save_message = 'Skipped saving user profile for CMAB experiment.'
+                self.logger.debug(save_message)
+                decide_reasons.append(save_message)
             return {
                 'cmab_uuid': cmab_uuid,
                 'error': False,
diff --git a/tests/test_decision_service.py b/tests/test_decision_service.py
index dbcb743..04a8747 100644
--- a/tests/test_decision_service.py
+++ b/tests/test_decision_service.py
@@ -1074,6 +1074,93 @@ def test_get_variation_cmab_experiment_with_whitelisted_variation(self):
             mock_bucket.assert_not_called()
             mock_cmab_decision.assert_not_called()
 
+    def test_get_variation_cmab_experiment_excludes_user_profile_service(self):
+        """Test that CMAB experiments exclude User Profile Service for sticky bucketing."""
+
+        # Create a user context
+        user = optimizely_user_context.OptimizelyUserContext(
+            optimizely_client=None,
+            logger=None,
+            user_id="test_user",
+            user_attributes={}
+        )
+
+        # Create a CMAB experiment
+        cmab_experiment = entities.Experiment(
+            '111150',
+            'cmab_experiment',
+            'Running',
+            '111150',
+            [],  # No audience IDs
+            {},
+            [
+                entities.Variation('111151', 'variation_1'),
+                entities.Variation('111152', 'variation_2')
+            ],
+            [
+                {'entityId': '111151', 'endOfRange': 5000},
+                {'entityId': '111152', 'endOfRange': 10000}
+            ],
+            cmab={'trafficAllocation': 5000}
+        )
+
+        # Create a mock user profile service and tracker
+        mock_ups = mock.Mock(spec=user_profile.UserProfileService)
+        mock_tracker = mock.Mock(spec=user_profile.UserProfileTracker)
+        mock_tracker.get_user_profile.return_value = user_profile.UserProfile(
+            user_id="test_user",
+            experiment_bucket_map={'111150': {'variation_id': '111151'}}
+        )
+
+        with mock.patch('optimizely.helpers.experiment.is_experiment_running', return_value=True), \
+            mock.patch('optimizely.helpers.audience.does_user_meet_audience_conditions', return_value=[True, []]), \
+            mock.patch.object(self.decision_service.bucketer, 'bucket_to_entity_id',
+                              return_value=['$', []]), \
+            mock.patch.object(self.decision_service, 'cmab_service') as mock_cmab_service, \
+            mock.patch.object(self.project_config, 'get_variation_from_id',
+                              return_value=entities.Variation('111152', 'variation_2')), \
+            mock.patch.object(self.decision_service, 'get_stored_variation') as mock_get_stored, \
+            mock.patch.object(self.decision_service, 'logger') as mock_logger:
+
+            # Configure CMAB service to return a different variation than stored
+            mock_cmab_service.get_decision.return_value = (
+                {
+                    'variation_id': '111152',
+                    'cmab_uuid': 'test-cmab-uuid-456'
+                },
+                []
+            )
+
+            # Call get_variation with CMAB experiment and user profile tracker
+            variation_result = self.decision_service.get_variation(
+                self.project_config,
+                cmab_experiment,
+                user,
+                mock_tracker
+            )
+
+            variation = variation_result['variation']
+            cmab_uuid = variation_result['cmab_uuid']
+            reasons = variation_result['reasons']
+
+            # Verify that UPS was NOT consulted (get_stored_variation should not be called)
+            mock_get_stored.assert_not_called()
+
+            # Verify that the user profile tracker was NOT updated
+            mock_tracker.update_user_profile.assert_not_called()
+
+            # Verify decision reasons include UPS exclusion messages
+            self.assertIn('Skipped user profile lookup for CMAB experiment.', reasons)
+            self.assertIn('Skipped saving user profile for CMAB experiment.', reasons)
+
+            # Verify the variation is from CMAB service, not from stored profile
+            self.assertEqual(entities.Variation('111152', 'variation_2'), variation)
+            self.assertEqual('test-cmab-uuid-456', cmab_uuid)
+
+            # Verify logger was called with UPS skip messages
+            mock_logger.debug.assert_any_call('Skipped user profile lookup for CMAB experiment.')
+            mock_logger.debug.assert_any_call('Skipped saving user profile for CMAB experiment.')
+
 
 class FeatureFlagDecisionTests(base.BaseTest):
     def setUp(self):