Impetigo is a bacterial infection of the superficial layer of the epidermis with crusting or bullae caused by Streptococcus spp., Staphylococcus spp., or both. A 14-yr-old red-tailed monkey (Cercopithecus ascanius) presented with recurrent scabbing and ulceration under the nares over an 8-yr period. Repeated cultures and biopsy samples led to a presumptive diagnosis of impetigo, later confirmed on necropsy. Multiple antibiotic regimens were employed with varying success during multiple episodes, while lesions resolved on their own at other times. This condition has not been previously reported in a nonhuman primate, although it is not uncommon in humans.