For years, toothed belts have enjoyed a solid position in industry. In the engineering of devices, however, they have been seldom used up to now. Progress in profile geometry and optimized belt materials however today allow their use in high output applications that up to now have been in the province of the gear wheel and chain drives. The discussion covers introduction; and small and wear resistant toothed belts. A polyurethane-high strength aramid fiber mixture about 1 mm toothed belt can take 50 N loads per millimeter of belt width. Because of new technologies and improved materials, miniaturized toothed gears can be manufactured. Although they can not compete with the stiffness and maximum transferable torque if toothed wheel gears in use up to now, their operating properties such as freedom of play and noise dampening combined with their low cost are good arguments for their use in the engineering of devices. Lubricant-free miniaturized tooth gears and their long service life are other advantages. Applications in medicine, household devices, and vehicle engineering are expected to profit from their use after the assortment of small belt parts is further improved. Special solutions are also of interest in the engineering of devices.