During the decade, February, 1965, through February, 1975, 248 patients underwent renal transplantation at the Duke Medical Center. One hundred twenty-five were living related recipients, while 123 were cadaveric recipients. Eleven patients developed ileocolonic perforation. Six cases were felt to represent non-immunologic etiologies while the remaining five were felt to be associated with the allograft response and high dose steroid therapy. Only three of the patients survived this complication and in each case the perforation was localized. High dose steroid therapy interferes with prompt diagnosis and severely impairs successful treatment. Radiologists must be familiar with the problem of ileocolonic perforation in patients on steroid therapy, must have a high index of suspicion of the site of perforation, and must recommend and complete water soluble contrast examination for establishment of the diagnosis. Early diagnosis, prompt surgical intervention, and discontinuation of immunosuppressive therapy ...