A cohort of 429 patients who received kidney grafts between 1973 and 2007 at our hospital was studied for the incidence and sites of malignancy. Sixty-two malignant diseases developed in 57 of 429 patients (13.3%). The cumulative incidences of malignancy increased markedly in the second and third posttransplantation decades. The overall rates were 1.8% at 5 years, 6.7% at 10 years, 12.5% at 15 years, 17.3% at 20 years, and 25.6% at 25 years. In the second and third posttransplantation decades, patients without malignancy showed significantly superior survival versus than those with cancer (P = .0002). Their survival rates were 83.4% versus 86.9% at 10 years and 63.1% versus 80.3% at 20 years, respectively. Skin cancer, renal cell carcinoma of the native kidney, hepatocellular carcinoma, posttransplantation lymphoproliferative disease, uterine cancer, and colorectal cancer were common in our series. The 5-year survival rates after the treatment of malignancy were better for skin cancer and renal cell carcinoma of the native kidney. Concerning the effects of immunosuppression, the tacrolimus-based group displayed a higher incidence among 3 groups (P = .0044).