We describe two patients with paraneoplastic cerebellar syndromes who gained clinically useful neurologic remissions following radical excision of the primary cancer. In both patients the syndrome was characterized by the rapid onset of gait ataxia, nausea, postural vertigo, central positional nystagmus, and saccadic oscillations. These observations encourage radical treatment of the primary cancer in patients with advanced malignant neoplasms who are disabled by cerebellar dysfunction, and lend support to a current hypothesis that paraneoplastic cerebellar degeneration is due to anticerebellar Purkinje cell antibodies elaborated by the primary cancer.