diff --git a/pre_commit_hooks/requirements_txt_fixer.py b/pre_commit_hooks/requirements_txt_fixer.py
index ffabf2a..1ee6fac 100644
--- a/pre_commit_hooks/requirements_txt_fixer.py
+++ b/pre_commit_hooks/requirements_txt_fixer.py
@@ -63,9 +63,16 @@
         else:
             requirement.value = line
 
+    # if a file ends in a comment, preserve it at the end
+    if requirements[-1].value is None:
+        rest = requirements.pop().comments
+    else:
+        rest = []
+
     for requirement in sorted(requirements):
         after.extend(requirement.comments)
         after.append(requirement.value)
+    after.extend(rest)
 
     after_string = b''.join(after)