diff --git a/docs/command-line.rst b/docs/command-line.rst
index 39ee2fff..25be620f 100644
--- a/docs/command-line.rst
+++ b/docs/command-line.rst
@@ -66,6 +66,7 @@ Environment variables
 +--------------------------+--------------------------------------------------+
 | ``DL_DIR``               | Environment variables that are transferred to    |
 | ``SSTATE_DIR``           | the bitbake environment.                         |
+| ``SSTATE_MIRRORS``       |                                                  |
 | ``TMPDIR``               |                                                  |
 +--------------------------+--------------------------------------------------+
 | ``http_proxy``           | These variables define the proxy configuration   |
diff --git a/kas/libkas.py b/kas/libkas.py
index 613b38ae..24d55ffa 100644
--- a/kas/libkas.py
+++ b/kas/libkas.py
@@ -278,7 +278,7 @@ def get_build_environ(build_system):
 
     conf_env = get_context().config.get_environment()
 
-    env_vars = ['SSTATE_DIR', 'DL_DIR', 'TMPDIR']
+    env_vars = ['SSTATE_DIR', 'SSTATE_MIRRORS', 'DL_DIR', 'TMPDIR']
     env_vars.extend(conf_env)
 
     env.update(conf_env)