We describe our initial experience of a method which develops the role of endoscopic surgery in the treatment of early prostatic carcinoma. An "extended" transurethral resection of the prostate (TURP) under ultrasound control reduces the prostatic tissue to a thin residual capsule suitable for subsequent transmural coagulation by endoscopic YAG laser. Twenty patients with early disease were entered into the pilot study. Three were excluded after staging (2 T0a and 1 with positive nodes on pelvioscopy-T2 N1 M0); 17 received a full course of treatment. Mean follow-up was 6 months (range 1-14). Two early patients with excessive residual tissue had initially positive biopsies and underwent second treatments with subsequently negative biopsies. Two patients continue to have positive biopsies and the rest are negative. No tumour has progressed and complications have been minimal. One patient experienced reduced frequency of erections and 1 required bladder neck incision for symptomatic bladder neck stenosis at routine follow-up endoscopy. There were no other effects on either potency or continence.