diff --git a/.pre-commit-hooks.yaml b/.pre-commit-hooks.yaml
index b71169bb..278331e0 100644
--- a/.pre-commit-hooks.yaml
+++ b/.pre-commit-hooks.yaml
@@ -192,7 +192,7 @@
     always_run: true
 -   id: requirements-txt-fixer
     name: fix requirements.txt
-    description: sorts entries in requirements.txt.
+    description: sorts entries in requirements.txt and checks whether a version is specified (parameterized).
     entry: requirements-txt-fixer
     language: python
     files: (requirements|constraints).*\.txt$
diff --git a/README.md b/README.md
index c0f678fd..74e2425b 100644
--- a/README.md
+++ b/README.md
@@ -187,6 +187,9 @@ the following commandline options:
 
 #### `requirements-txt-fixer`
 Sorts entries in requirements.txt and constraints.txt and removes incorrect entry for `pkg-resources==0.0.0`
+Provides also an optional check if a version is specified for each requirement. You can configure this with
+the following commandline options:
+  - `--fail-without-version` - Fails when no version is specified for a requirement
 
 #### `sort-simple-yaml`
 Sorts simple YAML files which consist only of top-level
diff --git a/pre_commit_hooks/requirements_txt_fixer.py b/pre_commit_hooks/requirements_txt_fixer.py
index 8ce8ec64..04590e43 100644
--- a/pre_commit_hooks/requirements_txt_fixer.py
+++ b/pre_commit_hooks/requirements_txt_fixer.py
@@ -13,6 +13,7 @@
 class Requirement:
     UNTIL_COMPARISON = re.compile(b'={2,3}|!=|~=|>=?|<=?')
     UNTIL_SEP = re.compile(rb'[^;\s]+')
+    VERSION_SPECIFIED = re.compile(b'.+(={2,3}|!=|~=|>=?|<=?).+')
 
     def __init__(self) -> None:
         self.value: bytes | None = None
@@ -58,6 +59,12 @@ def is_complete(self) -> bool:
             not self.value.rstrip(b'\r\n').endswith(b'\\')
         )
 
+    def contains_version_specifier(self) -> bool:
+        return (
+            self.value is not None and
+            bool(self.VERSION_SPECIFIED.match(self.value))
+        )
+
     def append_value(self, value: bytes) -> None:
         if self.value is not None:
             self.value += value
@@ -65,7 +72,7 @@ def append_value(self, value: bytes) -> None:
             self.value = value
 
 
-def fix_requirements(f: IO[bytes]) -> int:
+def fix_requirements(f: IO[bytes], fail_without_version: bool) -> int:
     requirements: list[Requirement] = []
     before = list(f)
     after: list[bytes] = []
@@ -121,6 +128,17 @@ def fix_requirements(f: IO[bytes]) -> int:
         ]
     ]
 
+    # check for requirements without a version specified
+    if fail_without_version:
+        missing_requirement_found = False
+        for req in requirements:
+            if not req.contains_version_specifier():
+                print(f'Missing version for requirement {req.name.decode()}')
+                missing_requirement_found = True
+
+        if missing_requirement_found:
+            return FAIL
+
     # sort the requirements and remove duplicates
     prev = None
     for requirement in sorted(requirements):
@@ -136,6 +154,7 @@ def fix_requirements(f: IO[bytes]) -> int:
     if before_string == after_string:
         return PASS
     else:
+        print('Sorting requirements')
         f.seek(0)
         f.write(after_string)
         f.truncate()
@@ -145,16 +164,22 @@ def fix_requirements(f: IO[bytes]) -> int:
 def main(argv: Sequence[str] | None = None) -> int:
     parser = argparse.ArgumentParser()
     parser.add_argument('filenames', nargs='*', help='Filenames to fix')
+    parser.add_argument(
+        '--fail-without-version', action='store_true',
+        help='Fail if a requirement is missing a version',
+    )
     args = parser.parse_args(argv)
 
     retv = PASS
 
     for arg in args.filenames:
         with open(arg, 'rb+') as file_obj:
-            ret_for_file = fix_requirements(file_obj)
+            ret_for_file = fix_requirements(
+                file_obj, args.fail_without_version,
+            )
 
             if ret_for_file:
-                print(f'Sorting {arg}')
+                print(f'Error in file {arg}')
 
             retv |= ret_for_file
 
diff --git a/tests/requirements_txt_fixer_test.py b/tests/requirements_txt_fixer_test.py
index c0d2c65d..b35585ce 100644
--- a/tests/requirements_txt_fixer_test.py
+++ b/tests/requirements_txt_fixer_test.py
@@ -9,43 +9,49 @@
 
 
 @pytest.mark.parametrize(
-    ('input_s', 'expected_retval', 'output'),
+    ('input_s', 'argv', 'expected_retval', 'output'),
     (
-        (b'', PASS, b''),
-        (b'\n', PASS, b'\n'),
-        (b'# intentionally empty\n', PASS, b'# intentionally empty\n'),
-        (b'foo\n# comment at end\n', PASS, b'foo\n# comment at end\n'),
-        (b'foo\nbar\n', FAIL, b'bar\nfoo\n'),
-        (b'bar\nfoo\n', PASS, b'bar\nfoo\n'),
-        (b'a\nc\nb\n', FAIL, b'a\nb\nc\n'),
-        (b'a\nc\nb', FAIL, b'a\nb\nc\n'),
-        (b'a\nb\nc', FAIL, b'a\nb\nc\n'),
+
+        (b'', [], PASS, b''),
+        (b'\n', [], PASS, b'\n'),
+        (b'# intentionally empty\n', [], PASS, b'# intentionally empty\n'),
+        (b'foo\n# comment at end\n', [], PASS, b'foo\n# comment at end\n'),
+        (b'foo\nbar\n', [], FAIL, b'bar\nfoo\n'),
+        (b'bar\nfoo\n', [], PASS, b'bar\nfoo\n'),
+        (b'a\nc\nb\n', [], FAIL, b'a\nb\nc\n'),
+        (b'a\nc\nb', [], FAIL, b'a\nb\nc\n'),
+        (b'a\nb\nc', [], FAIL, b'a\nb\nc\n'),
         (
             b'#comment1\nfoo\n#comment2\nbar\n',
+            [],
             FAIL,
             b'#comment2\nbar\n#comment1\nfoo\n',
         ),
         (
             b'#comment1\nbar\n#comment2\nfoo\n',
+            [],
             PASS,
             b'#comment1\nbar\n#comment2\nfoo\n',
         ),
-        (b'#comment\n\nfoo\nbar\n', FAIL, b'#comment\n\nbar\nfoo\n'),
-        (b'#comment\n\nbar\nfoo\n', PASS, b'#comment\n\nbar\nfoo\n'),
+        (b'#comment\n\nfoo\nbar\n', [], FAIL, b'#comment\n\nbar\nfoo\n'),
+        (b'#comment\n\nbar\nfoo\n', [], PASS, b'#comment\n\nbar\nfoo\n'),
         (
             b'foo\n\t#comment with indent\nbar\n',
+            [],
             FAIL,
             b'\t#comment with indent\nbar\nfoo\n',
         ),
         (
             b'bar\n\t#comment with indent\nfoo\n',
+            [],
             PASS,
             b'bar\n\t#comment with indent\nfoo\n',
         ),
-        (b'\nfoo\nbar\n', FAIL, b'bar\n\nfoo\n'),
-        (b'\nbar\nfoo\n', PASS, b'\nbar\nfoo\n'),
+        (b'\nfoo\nbar\n', [], FAIL, b'bar\n\nfoo\n'),
+        (b'\nbar\nfoo\n', [], PASS, b'\nbar\nfoo\n'),
         (
             b'pyramid-foo==1\npyramid>=2\n',
+            [],
             FAIL,
             b'pyramid>=2\npyramid-foo==1\n',
         ),
@@ -58,6 +64,7 @@
             b'd>2\n'
             b'g<2\n'
             b'f<=2\n',
+            [],
             FAIL,
             b'a==1\n'
             b'bbbb!=1\n'
@@ -68,24 +75,27 @@
             b'f<=2\n'
             b'g<2\n',
         ),
-        (b'a==1\nb==1\na==1\n', FAIL, b'a==1\nb==1\n'),
+        (b'a==1\nb==1\na==1\n', [], FAIL, b'a==1\nb==1\n'),
         (
             b'a==1\nb==1\n#comment about a\na==1\n',
+            [],
             FAIL,
             b'#comment about a\na==1\nb==1\n',
         ),
-        (b'ocflib\nDjango\nPyMySQL\n', FAIL, b'Django\nocflib\nPyMySQL\n'),
+        (b'ocflib\nDjango\nPyMySQL\n', [], FAIL, b'Django\nocflib\nPyMySQL\n'),
         (
             b'-e git+ssh://git_url@tag#egg=ocflib\nDjango\nPyMySQL\n',
+            [],
             FAIL,
             b'Django\n-e git+ssh://git_url@tag#egg=ocflib\nPyMySQL\n',
         ),
-        (b'bar\npkg-resources==0.0.0\nfoo\n', FAIL, b'bar\nfoo\n'),
-        (b'foo\npkg-resources==0.0.0\nbar\n', FAIL, b'bar\nfoo\n'),
-        (b'bar\npkg_resources==0.0.0\nfoo\n', FAIL, b'bar\nfoo\n'),
-        (b'foo\npkg_resources==0.0.0\nbar\n', FAIL, b'bar\nfoo\n'),
+        (b'bar\npkg-resources==0.0.0\nfoo\n', [], FAIL, b'bar\nfoo\n'),
+        (b'foo\npkg-resources==0.0.0\nbar\n', [], FAIL, b'bar\nfoo\n'),
+        (b'bar\npkg_resources==0.0.0\nfoo\n', [], FAIL, b'bar\nfoo\n'),
+        (b'foo\npkg_resources==0.0.0\nbar\n', [], FAIL, b'bar\nfoo\n'),
         (
             b'git+ssh://git_url@tag#egg=ocflib\nDjango\nijk\n',
+            [],
             FAIL,
             b'Django\nijk\ngit+ssh://git_url@tag#egg=ocflib\n',
         ),
@@ -95,6 +105,7 @@
             b' --hash=sha256:abcd\n'
             b'a=3.0.0 \\\n'
             b'  --hash=sha256:a1b1c1d1',
+            [],
             FAIL,
             b'a=3.0.0 \\\n'
             b'  --hash=sha256:a1b1c1d1\n'
@@ -104,16 +115,36 @@
         ),
         (
             b'a=2.0.0 \\\n --hash=sha256:abcd\nb==1.0.0\n',
+            [],
             PASS,
             b'a=2.0.0 \\\n --hash=sha256:abcd\nb==1.0.0\n',
         ),
+        (b'bar\nfoo\n', ['--fail-without-version'], FAIL, b'bar\nfoo\n'),
+        (
+            b'bar==1.0\nfoo==1.1a\n',
+            ['--fail-without-version'],
+            PASS,
+            b'bar==1.0\nfoo==1.1a\n',
+        ),
+        (
+            b'#test\nbar==1.0\nfoo==1.1a\n',
+            ['--fail-without-version'],
+            PASS,
+            b'#test\nbar==1.0\nfoo==1.1a\n',
+        ),
+        (
+            b'bar==1.0\n#test\nfoo==1.1a\n',
+            ['--fail-without-version'],
+            PASS,
+            b'bar==1.0\n#test\nfoo==1.1a\n',
+        ),
     ),
 )
-def test_integration(input_s, expected_retval, output, tmpdir):
+def test_integration(input_s, argv, expected_retval, output, tmpdir):
     path = tmpdir.join('file.txt')
     path.write_binary(input_s)
 
-    output_retval = main([str(path)])
+    output_retval = main([str(path)] + argv)
 
     assert path.read_binary() == output
     assert output_retval == expected_retval
@@ -130,6 +161,15 @@ def test_requirement_object():
     requirement_bar = Requirement()
     requirement_bar.value = b'bar'
 
+    requirements_bar_versioned = Requirement()
+    requirements_bar_versioned.value = b'bar==1.0'
+
+    # check for version specification
+    assert top_of_file.contains_version_specifier() is False
+    assert requirement_foo.contains_version_specifier() is False
+    assert requirement_bar.contains_version_specifier() is False
+    assert requirements_bar_versioned.contains_version_specifier() is True
+
     # This may look redundant, but we need to test both foo.__lt__(bar) and
     # bar.__lt__(foo)
     assert requirement_foo > top_of_file