Two cases of male infertility with pathological dilatation of ejaculatory duct are reported. In both cases, the dilatated wall of the ejaculatory duct was incised at the vermontanum with a cold knife endoscopically. After the incision, the findings of semen analysis of one case improved markedly and his wife became pregnant. In another case, semen analysis was not improved. Transurethral incision seemed to be a useful modality for the treatment of pathological dilatation of ejaculatory duct.