Between September, 1969, and December, 1978, 290 patients received 325 cadaveric renal allografts; 11 others transplanted elsewhere were also observed. Cancers developed in 28 patients (9.3%); 26 of these (93%) had skin cancers. The incidence of skin cancer increased by 5% annually after the first year of graft function, to a cumulative 44% in those surviving 9 years with functioning grafts. This represents an incidence of 4,356/100,000 person years of post-transplant risk--20.6 times the annual incidence of skin cancer in the general population of Southern Queensland. Half of the patients had multiple tumors when the first skin cancer was diagnosed, after a mean latent interval of 34 months. A total of 138 skin cancers occurred in 26 patients (average, 5.3 per patient), with a maximum of 19 in one individual. The ratio of basal to squamous cell carcinoma was reversed from 4:1, in the general population, to 1:1.7. Conventional surgical excision gave satisfactory results, with the one local recurrence being controlled by reexcision. Two patients (7%) died of melanoma and metastatic squamous cell carcinoma, respectively, whereas two of the other four patients who died from cancer had coincidental skin cancer. The two skin cancer deaths represent only 2% of all deaths in allograft recipients. These results suggest that the problem of skin cancer in these patients can be controlled and thus is not a significant contraindication to the continued clinical use of cadaveric renal transplantation.