BACKGROUND Whereas rejection was reported to be the most common cause of renal allograft rupture (RAR) in the pre-cyclosporin era, renal vein thrombosis (RVT) is purported to be the main cause of RAR in patients taking cyclosporin. The extremely low incidence of RVT in our series (0.11%) prompted us to analyse our collective with regard to RAR. METHODS Between 1974 and 1999, 1811 renal transplants were performed. Patients with RAR, defined as a tear of the renal capsule and parenchyma, were identified and possible underlying factors studied. RESULTS RAR was diagnosed in nine male and five female recipients (0.8%) with a median age of 36 years. Immunosuppression consisted of azathioprine and prednisolone in seven patients and of cyclosporin-based therapy in the seven others. At exploration five grafts were removed immediately: three because of irreversible rejection, one because of deep wound infection, and one with a twisted renal vein. Six of the nine salvaged kidneys have been functioning after a mean observation time of 45 months. In the pre-cyclosporin era RAR was associated with acute rejection in five out of seven cases as compared with only three of the seven on cyclosporin treatment. Core biopsies might have been the cause in three cases. CONCLUSIONS RAR is a rare complication after renal transplantation. Acute rejection still represents the most frequent cause of RAR in the cyclosporin era.