Thirty-one renal transplantations were performed in 25 patients with end-stage polycystic disease of the kidneys. Of the 14 recipients transplanted with both polycystic kidneys in situ and followed for at least 6 months, 10 had a previous history of urinary tract infection. Four of these 14 recipients had relapsing urinary tract infection after transplantation, the other 10 have been at risk on immunosuppressive therapy for a total of 152 months and have had no trouble that could be attributed to the presence of the polycystic kidneys. Despite the potentiality of polycystic kidneys to be a source of post-transplant infection when left in situ, a good outcome of renal transplatation could be achieved without preparative bilateral nephrectomy. The one-year patient and graft survivals are comparable to those obtained in our total transplantation series and renal transplantation is considered to be an acceptable therapy in polycystic disease.