A series of 32 patients with carcinoma of the prostate who underwent 125iodine interstitial irradiation to the prostate and simultaneous extraperitoneal pelvic lymphadenectomy was reviewed. The patients were segregated into 3 groups: group 1-patients with early localized low grade disease, group 2-patients with advanced localized high grade disease and group 3-patients with early localized high grade disease and those with advanced localized low grade disease. Owing to the high degree of predictability of the absence or presence of pelvic lymph node metastasis in patients in groups 1 and 2 and the morbidity associated with superficial pelvic lymphadenectomy we do not advocate this procedure in these patients. However, we advocate pelvic lymphadenectomy in patients in group 3 because of the unpredictability of lymph node metastasis. Furthermore, our data indicate that 1) the morbidity of the combined procedures is relatively low, with no patients becoming incontinent and only 12.5 per cent becoming impotent, 2) 125iodine interstitial irradiation of the prostate after transurethral prostatectomy is safer in terms of postoperative complications than is radical prostatectomy and 3) while superficial pelvic lymphadenectomy is not an innocuous procedure it generally is safe and, at times, an important diagnostic staging procedure.