diff --git a/workers/tagbackfillworker.py b/workers/tagbackfillworker.py
index 42faddf0f..cedcc4134 100644
--- a/workers/tagbackfillworker.py
+++ b/workers/tagbackfillworker.py
@@ -8,11 +8,13 @@ from peewee import JOIN, fn, IntegrityError
 from app import app
 from data.database import (UseThenDisconnect, TagToRepositoryTag, RepositoryTag,
                            TagManifestToManifest, Tag, TagManifest, TagManifestToManifest, Image,
-                           Manifest, TagManifestLabel, ManifestLabel, TagManifestLabelMap, db_transaction)
+                           Manifest, TagManifestLabel, ManifestLabel, TagManifestLabelMap,
+                           Repository, db_transaction)
 from data.model import DataModelException
 from data.model.image import get_parent_images
 from data.model.tag import populate_manifest
 from data.model.blob import get_repo_blob_by_digest, BlobDoesNotExist
+from data.model.user import get_namespace_user
 from data.registry_model import pre_oci_model
 from data.registry_model.datatypes import Tag as TagDataType
 from image.docker.schema1 import (DockerSchema1Manifest, ManifestException, ManifestInterface,
@@ -109,19 +111,27 @@ class BrokenManifest(ManifestInterface):
 
 
 class TagBackfillWorker(Worker):
-  def __init__(self):
+  def __init__(self, namespace_filter=None):
     super(TagBackfillWorker, self).__init__()
+    self._namespace_filter = namespace_filter
+
     self.add_operation(self._backfill_tags, WORKER_TIMEOUT)
 
+  def _filter(self, query):
+    if self._namespace_filter:
+      namespace_user = get_namespace_user(self._namespace_filter)
+      query = query.join(Repository).where(Repository.namespace_user == namespace_user)
+
+    return query
+
   def _candidates_to_backfill(self):
     def missing_tmt_query():
-      return (RepositoryTag
-              .select()
+      return (self._filter(RepositoryTag.select())
               .join(TagToRepositoryTag, JOIN.LEFT_OUTER)
               .where(TagToRepositoryTag.id >> None, RepositoryTag.hidden == False))
 
-    min_id = (RepositoryTag.select(fn.Min(RepositoryTag.id)).scalar())
-    max_id = RepositoryTag.select(fn.Max(RepositoryTag.id)).scalar()
+    min_id = (self._filter(RepositoryTag.select(fn.Min(RepositoryTag.id))).scalar())
+    max_id = self._filter(RepositoryTag.select(fn.Max(RepositoryTag.id))).scalar()
 
     iterator = yield_random_entries(
       missing_tmt_query,
@@ -368,5 +378,5 @@ if __name__ == "__main__":
     while True:
       time.sleep(100000)
 
-  worker = TagBackfillWorker()
+  worker = TagBackfillWorker(app.config.get('BACKFILL_TAGS_NAMESPACE'))
   worker.start()