Boudin noir, before cooking.
Boudin (French pronunciation: [budɛ̃], from Middle French boud—cold cut) describes a number of different types of sausage used in French, Belgian, German, Quebec, Acadian, Creole, Austrian and Cajun cuisine.
Cajun-style fried Boudin balls
Cajun-style Boudin blanc that has been smoked.
- Boudin ball: A Cajun variation on boudin blanc. Instead of the filling's being stuffed into pork casings, it is rolled into a ball, battered, and deep fried.
- Boudin blanc: A white sausage made of pork without the blood. Pork liver and heart meat are typically included. In Cajun versions, the sausage is made from a pork rice dressing (much like dirty rice), which is stuffed into pork casings. Rice is always used in Cajun cuisine, whereas the French/Belgian version typically uses milk, and is therefore generally more delicate than the Cajun variety. In French/Belgian cuisine, the sausage is sauteed or grilled. The Louisiana version is normally simmered or braised, although coating with oil and slow grilling for tailgating is becoming a popular option in Lafayette, New Orleans, Houston and Baton Rouge.
- Boudin blanc de Rethel (pronounced: [bu.dɛ̃ blɑ̃ də ʁə.tɛl]: a traditional French boudin, which may only contain pork meat, fresh whole eggs and milk, and cannot contain any bread crumbs or flours/starches. It is protected under EU law with a PGI status.
- Boudin noir: A dark-hued blood sausage, containing pork, pig blood, and other ingredients. Variants of the boudin noir occur in French, Belgian, Cajun and Catalan cuisine. The Catalan version of the boudin noir is called botifarra negra. In the French Caribbean, it is known as boudin Créole.
- Boudin rouge: In Louisiana cuisine, a sausage similar to boudin blanc, but with pork blood added to it. This originated from the French boudin noir.
- Brown Rice Boudin: Brown-rice boudin is a flavor you won't find in many places. The taste is very similar to traditional pork boudin, except this boudin is made with a brown-rice substitute for those looking to cut down on white rice intake.
- Crawfish boudin: Popular in Cajun cuisine, crawfish boudin is made with the meat of crawfish tails added to rice. It is often served with cracklins (fried pig skins) and saltine crackers, hot sauce, and ice cold beer.
- Gator boudin: Made from alligator, gator boudin can be found sporadically in Louisiana and the Mississippi gulf coast.
- Shrimp Boudin: Similar to crawfish boudin, shrimp boudin is made by adding the shrimp to rice. It is great for appetizers or party food served in thin slices.
In the United States 
The term "boudin" in the Acadiana cultural region of Louisiana is commonly understood to refer only to boudin blanc and not to other variants. Boudin blanc is the staple boudin of this region and is the one most widely consumed. Also popular is seafood boudin consisting of crab, shrimp, and rice.
Cajun boudin is available most readily in southern Louisiana, particularly in the Lafayette, Lake Charles, and smaller, lesser known areas like Ville Platte (the north point of the "Cajun Triangle" where it tends to be a daily staple), though it may be found nearly anywhere in "Cajun Country", including eastern Texas. There are restaurants devoted to the speciality, though boudin is also sold from rice cookers in convenience stores along Interstate 10. Since boudin freezes well, it is shipped to specialty stores outside the region. Boudin is fast approaching the status of the stars of Cajun cuisine (e.g., dirty rice, étouffée, gumbo, and jambalaya) and has fanatic devotees who travel across Louisiana comparing the numerous homemade varieties.
Boudin Noir is available in Illinois in the Iroquois County towns of Papineau and Beaverville. The dish is the featured cuisine at the annual Beaverville Homecoming, held the first weekend of August. People travel from hundreds of miles to partake of the boudin.
"Le Boudin" 
Boudin gave rise to "Le Boudin", the official march of the French Foreign Legion. "Blood sausage" is a colloquial reference to the gear (rolled up in a red blanket) that used to top the backpacks of Legionnaires. The song makes repeated reference to the fact that the Belgians don't get any "blood sausage", since the King of the Belgians at one time forbade his subjects from joining the Legion (verse says "ce sont des tireurs au cul").
See also