diff --git a/keymapper/state.py b/keymapper/state.py
index 2d1714d6..f2cf1bd6 100644
--- a/keymapper/state.py
+++ b/keymapper/state.py
@@ -41,8 +41,13 @@ def populate_system_mapping():
     xmodmap = subprocess.check_output(['xmodmap', '-pke']).decode() + '\n'
     mappings = re.findall(r'(\d+) = (.+)\n', xmodmap)
     for keycode, names in mappings:
-        for name in names.split():
-            mapping[name] = int(keycode) - XKB_KEYCODE_OFFSET
+        # there might be multiple, like:
+        # keycode  64 = Alt_L Meta_L Alt_L Meta_L
+        # keycode 204 = NoSymbol Alt_L NoSymbol Alt_L
+        # only the first column is relevant. The others can be achieved
+        # by using a modifier button and the mapped key
+        name = names.split()[0]
+        mapping[name] = int(keycode) - XKB_KEYCODE_OFFSET
 
     for name, ecode in evdev.ecodes.ecodes.items():
         mapping[name] = ecode
diff --git a/tests/testcases/test_mapping.py b/tests/testcases/test_mapping.py
index 4245aebd..954db3ad 100644
--- a/tests/testcases/test_mapping.py
+++ b/tests/testcases/test_mapping.py
@@ -37,7 +37,12 @@ class TestMapping(unittest.TestCase):
         self.assertGreater(len(mapping), 100)
         self.assertEqual(mapping['1'], 2)
         self.assertEqual(mapping['KEY_1'], 2)
-        self.assertEqual(mapping['KEY_LEFTSHIFT'], mapping['Shift_L'])
+
+        self.assertEqual(mapping['Alt_L'], 56)
+        self.assertEqual(mapping['KEY_LEFTALT'], 56)
+
+        self.assertEqual(mapping['KEY_LEFTSHIFT'], 42)
+        self.assertEqual(mapping['Shift_L'], 42)
 
     def test_clone(self):
         mapping1 = Mapping()