diff --git a/pre_commit_hooks/requirements_txt_fixer.py b/pre_commit_hooks/requirements_txt_fixer.py
index 58843940..e088c0d6 100644
--- a/pre_commit_hooks/requirements_txt_fixer.py
+++ b/pre_commit_hooks/requirements_txt_fixer.py
@@ -116,7 +116,8 @@ def fix_requirements(f: IO[bytes]) -> int:
     for requirement in sorted(requirements):
         after.extend(requirement.comments)
         assert requirement.value, requirement.value
-        after.append(requirement.value)
+        if requirement.value not in after:
+            after.append(requirement.value)
     after.extend(rest)
 
     after_string = b''.join(after)
diff --git a/tests/requirements_txt_fixer_test.py b/tests/requirements_txt_fixer_test.py
index b725afa2..21c2fd8c 100644
--- a/tests/requirements_txt_fixer_test.py
+++ b/tests/requirements_txt_fixer_test.py
@@ -99,6 +99,8 @@
             PASS,
             b'a=2.0.0 \\\n --hash=sha256:abcd\nb==1.0.0\n',
         ),
+        (b'\nfoo\nfoo\n', FAIL, b'\nfoo\n'),
+        (b'\nbar\nfoo\nbar\n', FAIL, b'\nbar\nfoo\n'),
     ),
 )
 def test_integration(input_s, expected_retval, output, tmpdir):