We reviewed clinical findings and serologic data on 18 men and three women with paraneoplastic cerebellar degeneration (PCD) associated with Hodgkin's disease (HD). The patients were 20 to 77 years old (median, 44). The lymphoma preceded neurologic symptoms by 1 to 54 months in 17/21 patients, but stage or activity did not correlate with severity of neurologic disease; six developed PCD while in HD remission. PCD evolved subacutely (over weeks to months) and was pancerebellar in most. Ten had downbeat nystagmus. Thirteen stabilized in a disabled state (wheelchair- or bed-bound), five stabilized ambulatory, and three, who had progressed to a nonambulatory state, recovered. The clinical findings were usually only cerebellar but one patient had an encephalopathy, three long-tract signs, and two sensory neuropathy. Plasmapheresis (seven patients) and corticosteroids or other immunosuppressant medication (eight patients) did not help; one improved dramatically after treatment with clonazepam. Two patients improved spontaneously. Six patients had serum antibodies that reacted specifically with Purkinje cells. The pattern was distinct from that of PCD with gynecologic cancer (anti-Yo) or small-cell lung cancer (anti-Hu). Western blotting failed to identify a discrete Purkinje cell antigen. Seropositive patients did not differ clinically from their seronegative counterparts. HD-associated PCD is more common in men and in a younger age group than in PCD with other malignancies.