Prostate cancer is the most common malignant disease in men in western societies. Extracapsular spread of carcinoma is found in approximately half of the patients that are treated by radical prostatectomy. Recently, a new prostate-specific membrane glycoprotein was cloned and sequenced. A highly sensitive and specific nested reverse transcriptase polymerase chain reaction has been developed to detect early occult haematogeneous micrometastatic prostate cells. We analysed venous samples from 17 patients with metastatic prostate cancer using a modified reaction assay. This showed presence of micrometastatic prostate cells in 14 patients. Molecular detection of circulating prostatic epithelial cells could improve clinical staging and treatment of early prostate cancer.