Anti-Yo is the most frequent antibody associated with pure paraneoplastic cerebellar degeneration. Cerebellar degeneration may be associated with anti-Hu antibody but other signs of nervous system involvement occur during the course of the disease. We report the case of a 69-year old man presenting with a severe acute cerebellar dysfunction of sudden onset. High titers of anti-Hu antibodies were detected in serum and cerebrospinal fluid by immunohistochemistry and western blot. No other neurological symptom was found after a follow-up of 18 months. Biopsy of a mediastinal lymph node revealed a poorly differentiated carcinoma. We suggest that the course of the anti-Hu syndrome may rarely be similar to the anti-Yo syndrome.