The peanut butter and jelly sandwich (PBJ or PB&J) is a common sandwich in the United States and Canada. Children are the largest consumers of PB&J sandwiches, usually eating them for lunch.

The recipe is as simple as the name -- one slice of bread spread with peanut butter, the other spread with jelly, jam, marmalade, or preserves. Because the jelly will not slide or drip off the bread when it is put together with the peanut butter slice, even a child can master its preparation. Elvis Presley made famous a version of the peanut butter sandwich with banana (either mashed or whole) that was grilled or fried, and may have contained bacon.

The origin of the peanut butter and jelly sandwich probably dates to the early years of the 20th century. Peanut butter was first widely introduced in 1904 at the Louisiana Purchase Exposition although it had been sold as a medical nutritional supplement in Saint Louis, Missouri, for about 15 years.

PB&J sandwiches are also popular because they can be kept for relatively long periods without refrigeration (unlike, for example, a ham and cheese with mayonnaise).

The United States Department of Defense is researching ways of preserving a PB&J for up to 3 years for its combat troops in the field. Previously, peanut butter and jelly has been available in the military instant food Meal, Ready-to-Eat (MRE) for many years. However, it is very difficult to preserve bread for so many years.

In December 1999, The J.M. Smucker Co. was granted a patent on a type of peanut butter and jelly sandwich without a crust—a "sealed crustless sandwich"—and began contacting other sandwich manufacturers with cease and desist letters. On April 8, 2005, "the U.S. Court of Appeals for the Federal Circuit rejected an effort by J.M. Smucker Co. to patent its process for making pocket-size peanut butter and jelly pastries called Uncrustables. " [1]