diff --git a/src/openai/cli/_api/audio.py b/src/openai/cli/_api/audio.py
index eaf57748ad..ca163b674b 100644
--- a/src/openai/cli/_api/audio.py
+++ b/src/openai/cli/_api/audio.py
@@ -65,6 +65,9 @@ def transcribe(args: CLITranscribeArgs) -> None:
         with open(args.file, "rb") as file_reader:
             buffer_reader = BufferReader(file_reader.read(), desc="Upload progress")
 
+        # add the file extension otherwise file format detection fails
+        buffer_reader.name = "audio." + args.file.split(".")[-1]
+
         model = get_client().audio.transcriptions.create(
             file=buffer_reader,
             model=args.model,
@@ -82,6 +85,8 @@ def translate(args: CLITranslationArgs) -> None:
         with open(args.file, "rb") as file_reader:
             buffer_reader = BufferReader(file_reader.read(), desc="Upload progress")
 
+        buffer_reader.name = "audio." + args.file.split(".")[-1]
+
         model = get_client().audio.translations.create(
             file=buffer_reader,
             model=args.model,