Paraneoplastic syndromes arise infrequently in prostate cancer and paraneoplastic subacute sensory neuronopathy has not previously been reported in association with prostate cancer. When paraneoplastic syndromes occur, it is usually in the setting of small-cell carcinoma of the prostate or advanced, hormone-resistant disease. Here the authors report a 64- year-old man who developed a progressive, severe, sensory neuronopathy in the setting of a recently diagnosed stage T4 hormone-responsive prostate adenocarcinoma. Anti-Hu antibodies were positive and screening for a concurrent neoplasm at another site was negative. Sensory neuronopathy progressed, despite hormone responsiveness of his prostate adenocarcinoma, and resulted in a severe level of disability. His symptoms did not respond to intravenous corticosteroid therapy but there was a partial response to intravenous immunoglobulin.