Cytomegalovirus (CMV) infection in immunocompromised patients is a major cause of morbidity and mortality. A well-documented manifestation of gastrointestinal CMV infection is gastrointestinal haemorrhage. In contrast, CMV-associated intestinal perforation has rarely been reported after transplantation, although it is well documented in AIDS patients. Three patients are reported who received their first cadaveric renal transplant in 1994 and subsequently developed CMV disease. During the course of their CMV illness, which was treated with ganciclovir, each presented with clinical suspicion of peritonitis and proceeded to laparotomy. All three were found to have sigmoid colon perforations with histological evidence of CMV infection. Following bowel resection and defunctioning, two patients made an uneventful recovery and have had the continuity of their bowel restored, but one died of overwhelming sepsis within hours of surgery. The explanation for the apparent clustering of this rare condition in transplant patients is uncertain.