diff --git a/lib/ds9_basic.py b/lib/ds9_basic.py
index 11441b3..86cf0a9 100644
--- a/lib/ds9_basic.py
+++ b/lib/ds9_basic.py
@@ -390,7 +390,7 @@ def load_region(self, region_name):
 
     def set_region(self, region_string):
         if region_string[-1] != "\n":
-            region_string = region_string + "\n"
+            region_string = region_string + b"\n"
 
         self.set("regions", region_string)