diff --git a/contrib/byteify-strings.py b/contrib/byteify-strings.py
--- a/contrib/byteify-strings.py
+++ b/contrib/byteify-strings.py
@@ -152,14 +152,14 @@ def replacetokens(tokens, opts):
             if not insideignoreblock:
                 ignorenextline = (
                     tokens[i - 1].type == token.COMMENT
-                    and tokens[i - 1].string == "#no-py3-transform"
+                    and tokens[i - 1].string == "# no-py3-transform"
                 )
             continue
 
         if t.type == token.COMMENT:
-            if t.string == "#py3-transform: off":
+            if t.string == "# py3-transform: off":
                 insideignoreblock = True
-            if t.string == "#py3-transform: on":
+            if t.string == "# py3-transform: on":
                 insideignoreblock = False
 
         if ignorenextline or insideignoreblock:
diff --git a/tests/test-byteify-strings.t b/tests/test-byteify-strings.t
--- a/tests/test-byteify-strings.t
+++ b/tests/test-byteify-strings.t
@@ -152,33 +152,33 @@ Test without attr*() as methods
 Test ignore comments
 
   $ cat > testfile.py <<EOF
-  > #py3-transform: off
+  > # py3-transform: off
   > "none"
   > "of"
   > 'these'
   > s = """should"""
   > d = '''be'''
-  > #py3-transform: on
+  > # py3-transform: on
   > "this should"
   > 'and this also'
   > 
-  > #no-py3-transform
+  > # no-py3-transform
   > l = "this should be ignored"
   > l2 = "this shouldn't"
   > 
   > EOF
   $ byteify_strings testfile.py
-  #py3-transform: off
+  # py3-transform: off
   "none"
   "of"
   'these'
   s = """should"""
   d = '''be'''
-  #py3-transform: on
+  # py3-transform: on
   b"this should"
   b'and this also'
   
-  #no-py3-transform
+  # no-py3-transform
   l = "this should be ignored"
   l2 = b"this shouldn't"