diff --git a/litellm/llms/bedrock/chat/invoke_transformations/amazon_openai_transformation.py b/litellm/llms/bedrock/chat/invoke_transformations/amazon_openai_transformation.py
index ee07b71ef1..a438be1745 100644
--- a/litellm/llms/bedrock/chat/invoke_transformations/amazon_openai_transformation.py
+++ b/litellm/llms/bedrock/chat/invoke_transformations/amazon_openai_transformation.py
@@ -14,6 +14,7 @@ import httpx
 from litellm.llms.bedrock.base_aws_llm import BaseAWSLLM
 from litellm.llms.bedrock.common_utils import BedrockError
 from litellm.llms.openai.chat.gpt_transformation import OpenAIGPTConfig
+from litellm.passthrough.utils import CommonUtils
 from litellm.types.llms.openai import AllMessageValues
 
 if TYPE_CHECKING:
@@ -94,6 +95,9 @@ class AmazonBedrockOpenAIConfig(OpenAIGPTConfig, BaseAWSLLM):
             aws_bedrock_runtime_endpoint=aws_bedrock_runtime_endpoint,
             aws_region_name=aws_region_name,
         )
+
+        # Encode model ID for ARNs (e.g., :imported-model/ -> :imported-model%2F)
+        model_id = CommonUtils.encode_bedrock_runtime_modelid_arn(model_id)
         
         # Build the invoke URL
         if stream:
diff --git a/tests/llm_translation/test_bedrock_completion.py b/tests/llm_translation/test_bedrock_completion.py
index d23033c1e4..40ef2c3283 100644
--- a/tests/llm_translation/test_bedrock_completion.py
+++ b/tests/llm_translation/test_bedrock_completion.py
@@ -3517,7 +3517,7 @@ def test_bedrock_openai_imported_model():
         print(f"URL: {url}")
         assert "bedrock-runtime.us-east-1.amazonaws.com" in url
         assert (
-            "arn:aws:bedrock:us-east-1:117159858402:imported-model/m4gc1mrfuddy" in url
+            "arn:aws:bedrock:us-east-1:117159858402:imported-model%2Fm4gc1mrfuddy" in url
         )
         assert "/invoke" in url