Five patients with Salmonella typhimurium infection after a renal cadaveric graft are described. Salmonella were isolated from the urine of four patients, from the stool of one patient, from the blood of two patients, from the hip joint of one patient and from the cerebrospinal fluid of one patient. Infections were difficult to eradicate and necessitated prolonged antibiotic treatment. Renal function only deteriorated after the infection in some patients; salmonellosis could have triggered the rejection of the graft. Impaired cell-mediated immunity due to immunosuppressive drugs may be considered to be a predisposing factor for this kind of infection. Higher humoral antibody titers against Salmonella were found in the patients most clinically ill.