The cases of 99 consecutive recipients of first renal transplants were followed 6 to 38 months. "Ideal-risk" recipients were defined as those aged 17 to 45 years, with normal lower urinary tracts, and without infection and malignancy; 88% of ideal-risk recipients of related kidneys and 70% of ideal recipients of unrelated kidneys maintained good function for more than two years. There were identical results in 88% of "high-risk" recipients, including 18 children, six diabetics, eight patients older than 45 years, two with gastrointestinal ulceration, three with severe heart disease, three with abnormal bladder function, one with cystinosis, and one with lupus erythematosus. The only truly high-risk group of patients were those older than 45 who were recipients of cadaver transplants. Other high-risk factors are not absolute contraindications to transplantation.