Well, the differences may be subtle, but they're there. Cajun cooking grew out of French and Southern cuisines, and is more country-style. It makes much use of roux, and generally employs more spices than Creole cooking.

Creole cooking has Spanish, French, and African influences, and uses more butter, cream, and typically more tomatoes than Cajun cooking. Both types often call upon the holy trinity -- bell peppers, onions, and celery -- as the foundation of flavor.