diff --git a/README.md b/README.md
index 522abbf..d5b2cb5 100644
--- a/README.md
+++ b/README.md
@@ -60,6 +60,7 @@ jwt_secret: "your_jwt_secret"
 log_file: "./logs/app.log"
 image_storage_directory: "./images"
 ```
+The server also expects the CONFIG environment variable to be set. e.g. `export CONFIG=config/config.yaml`.
 
 ## Setup and Running