Anti-Purkinje cell antibodies (APCA), believed to be markers of paraneoplastic cerebellar degeneration in females, have been identified in the serum of 3 men with subacute sensory neuronopathies and no evidence of tumors 5 years after the onset of the neurological signs. By indirect immunohistochemistry on sections of rat cerebellum and dorsal root ganglia, the patients' IgG bound to the cytoplasms of both Purkinje cells and dorsal root ganglia neurons. By western blot analysis on whole human cerebellum and whole human dorsal root ganglia homogenates, the IgG from 2 patients bound to a 62-kd protein in both homogenates and the IgG from 1 patient bound to a 110-kd protein in the cerebellum homogenate only. Yo autoantibody test was negative in all patients. Our study provides evidence that non-anti-Yo APCA may be associated with subacute sensory neuronopathies and are not necessarily markers of an underlying tumor. The previously described anti-Yo APCA has only occurred in females with cancer.