We report the association of paraneoplastic cerebellar cortical degeneration with small-cell oesophageal carcinoma in a 60-year-old woman and describe the histopathological findings. We believe this to be the first report of such an occurrence. The cytoplasmic antigen PGP 9.5, which is strongly expressed in cerebellar Purkinje cells, was identified immunohistologically in the primary tumour and immunoglobulin demonstrated on Purkinje cells. These findings support an immunological pathogenesis for this condition and suggest that it is mediated by antibodies directed against tumour antigen which cross-react with Purkinje cells.