ABSTRACT:Sexual histories were obtained in 51 men with prostatic cancer and their spouses, before and after pelvic lymphadenectomy and retropubic125I implantation. The average age of the patients was 64.7 years. Sexual activity was retained in 40 of the 41 patients who were sexually active before operation. Ten patients had been sexually inactive before operation—4 with diminished potency and 6 with complete erectile impotence. Sexual dysfunction was most often pyschogenic. At six months after the operation, 5 of these patients had resumed satisfactory sexual intercourse as a result of reassurance, encouragement and education of the remaining sexual potential. No patient was rendered completely impotent as a result of the procedure. Preservation of sexual potency represents a significant advantage of125I implantation over other therapeutic modalities in the treatment of localized prostatic carcinom