diff --git a/Colorsets/ls_missing_colors.py b/Colorsets/ls_missing_colors.py
new file mode 100755
index 0000000..26067e0
--- /dev/null
+++ b/Colorsets/ls_missing_colors.py
@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+
+""" Searches xib and storyboard files for missing colors.
+
+If a named color is used in user interface file, and it is not present in 
+asset catalog it is considered missing.
+"""
+
+import os
+import pathlib
+import xml.etree.ElementTree
+
+# Find colors
+
+known_colors = []
+
+for dirpath, dirnames, filenames in os.walk('.'):
+    pure_path = pathlib.PurePath(dirpath)
+    directory_name = pure_path.name
+    if '.colorset' in directory_name:
+        known_colors.append(pure_path.stem)
+
+# Find user interface files
+
+filepaths = []
+
+for dirpath, dirnames, filenames in os.walk('.'):
+    for filename in filenames:
+        name_path = pathlib.PurePath(filename)
+        if name_path.suffix in [".xib", ".storyboard"]:
+            filepath = os.path.join(dirpath, name_path)
+            filepaths.append(filepath)
+
+# Check if user interface files contain unknown colors
+
+for filepath in filepaths:
+    tree = xml.etree.ElementTree.parse(filepath)
+    root = tree.getroot()
+    resources = root.find("resources")
+    if resources is None:
+        continue
+    for named_color in resources.findall("namedColor"):
+        color_name = named_color.get("name")
+        if color_name not in known_colors:
+            message = "warning: missing color: " + color_name + " used in: " + pathlib.PurePath(filepath).name
+            print(message)