diff --git a/CHANGELOG.md b/CHANGELOG.md
index a404ef5..3a67eb0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.12.17+1
+
+* Fix a bug where tags couldn't be marked as skipped.
+
 ## 0.12.17
 
 * Deprecate `expectAsync` and `expectAsyncUntil`, since they currently can't be
diff --git a/lib/src/backend/metadata.dart b/lib/src/backend/metadata.dart
index 013d91f..bdbf470 100644
--- a/lib/src/backend/metadata.dart
+++ b/lib/src/backend/metadata.dart
@@ -262,8 +262,8 @@
       new Metadata(
           testOn: testOn.intersection(other.testOn),
           timeout: timeout.merge(other.timeout),
-          skip: other._skip ?? _skip ,
-          skipReason: other.skipReason == null ? skipReason : other.skipReason,
+          skip: other._skip ?? _skip,
+          skipReason: other.skipReason ?? skipReason,
           verboseTrace: other._verboseTrace ?? _verboseTrace,
           tags: tags.union(other.tags),
           onPlatform: mergeMaps(onPlatform, other.onPlatform,
@@ -319,9 +319,9 @@
     return {
       'testOn': testOn == PlatformSelector.all ? null : testOn.toString(),
       'timeout': _serializeTimeout(timeout),
-      'skip': skip,
+      'skip': _skip,
       'skipReason': skipReason,
-      'verboseTrace': verboseTrace,
+      'verboseTrace': _verboseTrace,
       'tags': tags.toList(),
       'onPlatform': serializedOnPlatform,
       'forTag': mapMap(forTag,
diff --git a/pubspec.yaml b/pubspec.yaml
index 0020fa0..8ce4edd 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: test
-version: 0.12.17
+version: 0.12.17+1
 author: Dart Team <misc@dartlang.org>
 description: A library for writing dart unit tests.
 homepage: https://github.com/dart-lang/test
diff --git a/test/runner/configuration/tags_test.dart b/test/runner/configuration/tags_test.dart
index 3968edd..a4ff34c 100644
--- a/test/runner/configuration/tags_test.dart
+++ b/test/runner/configuration/tags_test.dart
@@ -132,6 +132,30 @@
       test.stdout.expect(consumeThrough(contains("+1: All tests passed!")));
       test.shouldExit(0);
     });
+
+    // Regression test for #503.
+    test("skips tests whose tags are marked as skip", () {
+      d.file("dart_test.yaml", JSON.encode({
+        "tags": {"foo": {"skip": "some reason"}}
+      })).create();
+
+      d.file("test.dart", """
+        import 'dart:async';
+
+        import 'package:test/test.dart';
+
+        void main() {
+          test("test 1", () => throw 'bad', tags: ['foo']);
+        }
+      """).create();
+
+      var test = runTest(["test.dart"]);
+      test.stdout.expect(containsInOrder([
+        "some reason",
+        "All tests skipped."
+      ]));
+      test.shouldExit(0);
+    });
   });
 
   group("include_tags and exclude_tags", () {