diff --git a/litellm/router.py b/litellm/router.py
index 1e1344deaa5..bc5f420dc83 100644
--- a/litellm/router.py
+++ b/litellm/router.py
@@ -225,6 +225,7 @@ class Router:
         redis_host: Optional[str] = None,
         redis_port: Optional[int] = None,
         redis_password: Optional[str] = None,
+        redis_db: Optional[int] = None,
         cache_responses: Optional[bool] = False,
         cache_kwargs: dict = {},  # additional kwargs to pass to RedisCache (see caching.py)
         caching_groups: Optional[
@@ -411,6 +412,12 @@ class Router:
             if redis_password is not None:
                 cache_config["password"] = redis_password
 
+            if redis_db is not None:
+                verbose_router_logger.warning(
+                    "Deprecated 'redis_db' argument used. Please remove 'redis_db' from your config/database and use 'cache_kwargs' instead."
+                )
+                cache_config["db"] = str(redis_db)
+
             # Add additional key-value pairs from cache_kwargs
             cache_config.update(cache_kwargs)
             redis_cache = self._create_redis_cache(cache_config)
diff --git a/tests/test_litellm/test_router_redis_init.py b/tests/test_litellm/test_router_redis_init.py
new file mode 100644
index 00000000000..4a8a5b57622
--- /dev/null
+++ b/tests/test_litellm/test_router_redis_init.py
@@ -0,0 +1,56 @@
+import pytest
+import asyncio
+import os
+from litellm import Router
+
+
+# Mark as async test
+@pytest.mark.asyncio
+async def test_router_uses_correct_redis_db():
+    """
+    Verifies that when redis_db is passed to Router,
+    items are actually stored in that specific Redis DB index.
+    """
+    # 1. Setup - Use a non-standard DB index (e.g., 5) to prove it's not using default 0
+    test_db_index = 5
+
+    # Ensure we have a Redis URL available (fallback to localhost if env var not set)
+    redis_host = os.getenv("REDIS_HOST", "localhost")
+    redis_port = os.getenv("REDIS_PORT", "6379")
+
+    # Initialize Router with specific redis_db
+    router = Router(
+        model_list=[
+            {
+                "model_name": "gpt-3.5-turbo",
+                "litellm_params": {"model": "gpt-3.5-turbo"},
+            }
+        ],
+        redis_host=redis_host,
+        redis_port=int(redis_port),
+        redis_db=test_db_index,
+        cache_responses=True,  # Important: Enable caching to trigger Redis usage
+    )
+
+    # 2. Verify Internal State
+    # Check if the underlying cache client is configured with the correct DB
+    # Accessing internal attributes for verification purposes
+    try:
+        if router.cache.redis_cache:
+            # Check connection kwargs or internal client db
+            cache_client = router.cache.redis_cache.redis_client
+            # Redis client stores connection args in connection_pool.connection_kwargs
+            conn_kwargs = cache_client.connection_pool.connection_kwargs
+
+            assert str(conn_kwargs.get("db")) == str(
+                test_db_index
+            ), f"Router Internal Check Failed: Expected DB {test_db_index}, got {conn_kwargs.get('db')}"
+        else:
+            pytest.fail("Redis cache was not initialized in Router")
+
+    except Exception as e:
+        pytest.fail(f"Failed to inspect Router internals: {e}")
+
+
+if __name__ == "__main__":
+    asyncio.run(test_router_uses_correct_redis_db())