A tumor removed from the skin of the right pectoral region of a 19-year-old male Capuchin monkey (Cebus albifrons) was morphologically classified as a papillary carcinoma of apocrine sweat gland origin. The designation of malignancy was based primarily on cellular pleomorphism and stromal invasion. This is believed to be the first report of this neoplasm in nonhuman primates. There has been no evidence of recurrence nor metastasis in the 12 months following excision.