diff --git a/pre_commit_hooks/requirements_txt_fixer.py b/pre_commit_hooks/requirements_txt_fixer.py
index 7849767..2c67d51 100644
--- a/pre_commit_hooks/requirements_txt_fixer.py
+++ b/pre_commit_hooks/requirements_txt_fixer.py
@@ -34,6 +34,10 @@ class Requirement:
         assert m is not None
 
         name = m.group()
+        if name == b'-i' or name.startswith(b'--index-url='):
+            return b'--index-url'
+        elif name.startswith(b'--extra-index-url='):
+            return b'--extra-index-url'
         m = self.UNTIL_COMPARISON.search(name)
         if not m:
             return name
diff --git a/tests/requirements_txt_fixer_test.py b/tests/requirements_txt_fixer_test.py
index bb75daa..6991bcd 100644
--- a/tests/requirements_txt_fixer_test.py
+++ b/tests/requirements_txt_fixer_test.py
@@ -116,6 +116,24 @@ from pre_commit_hooks.requirements_txt_fixer import Requirement
             b'--extra-index-url https://example.com/simple\n'
             b'requests\n',
         ),
+        (
+            b'--extra-index-url https://example.com/simple\n'
+            b'-i https://pypi.org/simple\n'
+            b'requests\n',
+            FAIL,
+            b'-i https://pypi.org/simple\n'
+            b'--extra-index-url https://example.com/simple\n'
+            b'requests\n',
+        ),
+        (
+            b'--extra-index-url=https://example.com/simple\n'
+            b'--index-url=https://pypi.org/simple\n'
+            b'requests\n',
+            FAIL,
+            b'--index-url=https://pypi.org/simple\n'
+            b'--extra-index-url=https://example.com/simple\n'
+            b'requests\n',
+        ),
     ),
 )
 def test_integration(input_s, expected_retval, output, tmpdir):