diff --git a/powerline/bindings/config.py b/powerline/bindings/config.py
index 31006330..eb6693b9 100644
--- a/powerline/bindings/config.py
+++ b/powerline/bindings/config.py
@@ -176,7 +176,7 @@ def init_tmux_environment(pl, args, set_tmux_environment=set_tmux_environment):
 		' ' * powerline.renderer.strwidth(left_dividers['hard'])))
 
 
-TMUX_VAR_RE = re.compile('\$(_POWERLINE_\w+)')
+TMUX_VAR_RE = re.compile(r'\$(_POWERLINE_\w+)')
 
 
 def tmux_setup(pl, args):