Colon perforation (CP) is an uncommon but dramatic complication after renal transplantation. Of 1530 consecutive kidney transplants performed at our center, 8 recipients had an CP (incidence of 0.5%), either early (n = 5, 2-14 days) or late (n = 3, 8-48 months) post transplant. Clinical symptoms were generally vague. Biological findings were inconstant. Risk factors for CP included a cadaver graft (versus a living donor), high body weight, history of diverticulitis, and Kayexalate use. Crucial to outcome were: 1) immediate diagnosis and 2) aggressive surgical care consisting of resectional therapy, broad-spectrum antibiotics, and reduced immunosuppression. Applying these principles, mortality in our patients (25%) was lower than in previously reported series (33-64%). All grafts were functioning at the time of diagnosis; graft function was preserved in recipients who recovered from CP. Patients with a documented history of diverticulitis should undergo prophylactic colonic resection. Constipation and colonic dilatation should be treated aggressively in the early post-operative period.