The style of cooking named for the French-speaking Acadian or 'Cajun' immigrants deported by the British from Acadia in Canada to the Acadiana region of Louisiana. It is a rustic cuisine — locally available ingredients predominate and preparation is simple. An authentic Cajun meal is usually a three-pot affair, with one pot dedicated to the main dish, one dedicated to steamed rice, skillet cornbread or some other grain dish, and the third containing whatever vegetable is plentiful or available.

The aromatic vegetables bell pepper (poivron), onion and celery are called by some chefs the holy trinity of Creole and Cajun cuisines. Roughly diced and combined in cooking, the method is similar to the use of the mire poix in traditional French cuisine — which blends roughly diced onion, celery, and carrot. Characteristic aromatics for the Cajun version may also include parsley, bay leaf, green onions and dried cayenne pepper.

Traditionally, Cajun cuisine would include smoked meats and preparations such as turkey or duck confit (preserved in poultry fat, with spices), but this is declining. However, game remains popular.

The recent increase of catfish farming in the Mississippi delta has brought about an increase in its usage in Cajun cuisine in the place of the more traditional wild sea trout and redfish. Crawfish, shrimp and crab are also commonly eaten.

Well-known Cajun dishes include boudin (a type of sausage made from pork, pork liver, rice, garlic, green onions and other spices), gumbo (a thick soup usually containing okra and often including seafood) and jambalaya (a combination of rice, chilli and various meats and vegetables).