What seed is traditionally found on a Chicago-style hot dog bun?

A Chicago-style hot dog traditionally comes on a poppy-seed bun. The bun is part of the familiar Chicago “dragged through the garden” combination: an all-beef frankfurter topped with yellow mustard, chopped onions, bright-green relish, tomato, a pickle spear, sport peppers, and celery salt.

The Chicago dog developed into a recognizable regional style in the early 20th century and became especially associated with inexpensive food stands during the Great Depression. Fluky's, founded in 1929, is often credited with helping popularize the all-beef version. Vienna Beef, another major Chicago name, also helped standardize the style.

The seed is sometimes omitted by individual vendors, so not every local hot dog has one. That variation does not change the canonical answer. The poppy seed is also easy to confuse with sesame, which appears on buns used for other sandwiches and regional hot dogs. Another famous Chicago-dog debate concerns ketchup: traditional versions generally exclude it.