diff --git a/src/python/adgui.py b/src/python/adgui.py
index 6fc6a28e..5f4ac665 100755
--- a/src/python/adgui.py
+++ b/src/python/adgui.py
@@ -147,7 +147,7 @@ def classify_devices():
         'avr_de': [],
         'other': []
     }
-    avr_de_re = re.compile('AVR\d+[DE][A-Z]\d+')
+    avr_de_re = re.compile(r'AVR\d+[DE][A-Z]\d+')
     part = ad.lfirst(ad.cvar.part_list)
     while part:
         p = ad.ldata_avrpart(part)