Neoplasms of the apocrine sweat glands accounted for 2.0 per cent and 3.6 per cent, respectively, of all canine and feline skin neoplasms diagnosed during a period of three years. They occurred in dogs from six to 17 years of age of both sexes, and golden retrievers appeared to be predisposed; they occurred in cats from six to 17 years of age and there were no breed or sex predilections. In both species, the neoplasms were usually solitary and occurred anywhere on the body; they were nearly always carcinomas and histologically were usually of the solid type. There were no clinical measurements that made it possible to distinguish reliably between benign and malignant lesions. No distant metastases were recorded, even though 22.5 per cent of the canine carcinomas had invaded the lymphatic system.