Blue cheese dressing is a popular salad dressing and dip in the United States. It is usually made of some combination of mayonnaise, and either or all buttermilk, sour cream or yogurt, blue cheese, milk, vinegar, onion powder, and garlic powder. There is a blue cheese vinaigrette that consists of salad oil, blue cheese, vinegar, and sometimes seasonings. There is also a Midwestern US version that consists of blue cheese crumbles in a California style French dressing.
Most major salad dressing producers and restaurants in the United States produce a variant of blue cheese dressing. It is commonly served as a dip with buffalo wings or crudités (raw vegetables).