Abstract: A tamper-resistant owner identification badge for bicycles comprises a hardened steel badge debossed with a registration number, a reward offer, and a toll-free phone number. An aluminum sticker inscribed with the owner's personal information is attached to the badge. The badge, formed by two opposing casing members, is mounted around the seatstay tube of a bicycle. Two screws sunken into counterbores hold the casing members firmly together. Sealing discs tapped flush into the counterbores permanently deny access to the screws, so that removal of the badge is extremely difficult for even the most experienced thieves. The personal information on the badge provides anyone who sees the bicycle, but particularly law enforcement authorities, a means to compare the person possessing the bicycle with the characteristics of the rightful owner. Even if the sticker is removed, the reward offer and the toll-free number will help to induce any person who finds the bicycle to report the discovery.