diff --git a/app/services/contact_service.py b/app/services/contact_service.py
index bc7fdad..e28c883 100644
--- a/app/services/contact_service.py
+++ b/app/services/contact_service.py
@@ -158,6 +158,16 @@ async def list_contacts(
     """
     from app.core.visibility import apply_visibility_filter
 
+    # I.4 Performance: Cache simple list queries (no search, no cursor, first 3 pages)
+    use_cache = not search and not cursor and page <= 3 and not folder_id
+    cache_key = f"contacts:list:{tenant_id}:{page}:{page_size}:{contact_type or 'all'}:{sort_by}:{sort_order}:{user_id or 'admin'}:{is_system_admin}"
+    if use_cache:
+        from app.core.cache import cache_get
+        cached = await cache_get(cache_key)
+        if cached:
+            return cached
+
+
     base = select(Contact).where(
         Contact.tenant_id == tenant_id,
         Contact.deleted_at.is_(None),
@@ -218,7 +228,7 @@ async def list_contacts(
     if use_keyset and len(contacts) == page_size and contacts:
         next_cursor = str(contacts[-1].id)
 
-    return {
+    result = {
         "items": [_serialize_contact(c) for c in contacts],
         "total": total,
         "page": page,
@@ -226,6 +236,13 @@ async def list_contacts(
         "next_cursor": next_cursor,
     }
 
+    # I.4 Performance: Cache the result for simple queries
+    if use_cache:
+        from app.core.cache import cache_set
+        await cache_set(cache_key, result, ttl=60)  # 60 second cache
+
+    return result
+
 
 async def get_contact(db: AsyncSession, tenant_id: uuid.UUID, contact_id: str,
                      user_id: uuid.UUID | None = None, is_system_admin: bool = False) -> dict: