diff --git a/doc/interop-test-descriptions.md b/doc/interop-test-descriptions.md
index 46cf7d5937150a73796df2b7f8c59cbf5fe09a5b..065e107c24944d6fdfe2948b431bca5037ada671 100644
--- a/doc/interop-test-descriptions.md
+++ b/doc/interop-test-descriptions.md
@@ -783,7 +783,7 @@ associated status messages end-to-end.
 When the client sends metadata with the key `"x-grpc-test-echo-initial"` with its
 request, the server sends back exactly this key and the corresponding value back to
 the client as part of initial metadata. When the client sends metadata with the key
-`"x-grpc-test-echo-trailing"` with its request, the server sends back exactly this
+`"x-grpc-test-echo-trailing-bin"` with its request, the server sends back exactly this
 key and the corresponding value back to the client as trailing metadata.
 
 ### Observe ResponseParameters.interval_us