This study evaluates sudomotor function in the hindpaw of young and aged mice. Sweating was stimulated by pilocarpine injection and by electrical stimulation of the sciatic, tibial, peroneal, sural and saphenous nerves. The number of responsive sweat glands of the paw was determined by the silicon mold technique. The results obtained provide evidence that the number of functioning sweat glands of the hindpaw tended to decrease in aged mice. The peripheral sudomotor territories and the complement of sweat glands for individual nerves declined slightly with age. Moreover, the number of sweat glands responsive to cholinergic stimulation was decreased when compared with the number responsive to electrical stimulation of the sciatic nerve in aged mice. These and previous observations suggest that the number of sudomotor axons in the peripheral nerve, as well as their capabilities for compensatory reinnervation of sweat glands by regeneration and by sprouting, is reduced with aging.