diff --git a/docs/ci/circleci.rst b/docs/ci/circleci.rst
index 61da49de..daf7e674 100644
--- a/docs/ci/circleci.rst
+++ b/docs/ci/circleci.rst
@@ -30,9 +30,9 @@ Put ``circle.yml`` to the root directory of the GitHub repository.
 
     machine:
         environment:
-            - PLATFORMIO_CI_SRC=path/to/source/file.c
-            - PLATFORMIO_CI_SRC=path/to/source/file.ino
-            - PLATFORMIO_CI_SRC=path/to/source/directory
+            PLATFORMIO_CI_SRC: path/to/source/file.c
+            PLATFORMIO_CI_SRC: path/to/source/file.ino
+            PLATFORMIO_CI_SRC: path/to/source/directory
 
     dependencies:
         pre: