diff --git a/src/vs/platform/theme/common/colorRegistry.ts b/src/vs/platform/theme/common/colorRegistry.ts
index f6bfcaaabfd..1e059b278fa 100644
--- a/src/vs/platform/theme/common/colorRegistry.ts
+++ b/src/vs/platform/theme/common/colorRegistry.ts
@@ -69,7 +69,7 @@ export interface IColorRegistry {
 
 }
 
-const colorPattern = '^#([0-9a-f]{3,4}|([0-9a-f]{2}){3,4})$';
+const colorPattern = '^#([0-9A-Fa-f]{3,4}|([0-9A-Fa-f]{2}){3,4})$';
 const colorPatternErrorMessage = nls.localize('invalid.color', 'Invalid color format. Use #RGB, #RGBA, #RRGGBB or #RRGGBBAA');
 
 class ColorRegistry implements IColorRegistry {