diff --git a/backend/app/routes.py b/backend/app/routes.py
index 5473cb8..8e3d367 100644
--- a/backend/app/routes.py
+++ b/backend/app/routes.py
@@ -4748,14 +4748,20 @@ def list_package_artifacts(
     if not package:
         raise HTTPException(status_code=404, detail="Package not found")
 
-    # Get distinct artifacts uploaded to this package via uploads table
-    artifact_ids_subquery = (
-        db.query(func.distinct(Upload.artifact_id))
+    # Get distinct artifacts for this package from both sources:
+    # 1. Upload table (traditional uploads)
+    # 2. PackageVersion table (PyPI proxy cached packages, version-based lookups)
+    upload_artifact_ids = (
+        db.query(Upload.artifact_id)
         .filter(Upload.package_id == package.id)
-        .subquery()
     )
+    version_artifact_ids = (
+        db.query(PackageVersion.artifact_id)
+        .filter(PackageVersion.package_id == package.id)
+    )
+    combined_artifact_ids = upload_artifact_ids.union(version_artifact_ids).subquery()
 
-    query = db.query(Artifact).filter(Artifact.id.in_(artifact_ids_subquery))
+    query = db.query(Artifact).filter(Artifact.id.in_(combined_artifact_ids))
 
     # Apply content_type filter
     if content_type: