Added by Scarecroe

Bart is Bert's twin brother on Sesame Street (EKA: Episode 0687), a traveling salesman by profession. Although they look identical, Bart is the complete opposite of Bert in personality -- he's cheerful, overbearing, and laughs a lot, a similarity shared with Ernie.

Bert once left to visit his brother, inciting Ernie to call him during the night about frivolous details such as being thirsty. Bart also sent Bert a book for his birthday in a 2003 episode, which Bert preferred to read quietly in observance of his special day.

Bart was presumably named after his (and Bert's) Uncle Bart.

Another segment featured an appearance by Bert's nephew, Brad, but no specific relationship between Brad and Bart is known.