Nonmelanoma skin cancer (NMSC) is a frequent complication after liver transplantation, but the risk factors of posttransplant NMSC have not been well defined. In a prospectively followed series of 170 liver transplant recipients, we assessed the incidence of NMSC, compared it with the expected incidence in the general population, and investigated which risk factors were related to NMSC. After a median follow-up of 62 months, 27 patients developed 43 NMSC. The relative risk of NMSC was 20.26 (95% confidence interval: 14.66-27.29) as compared with sex- and age-matched population. In univariate analysis, older age, male sex, Child-Turcotte-Pugh A or B at transplantation, treatment with mycophenolate mofetil, skin type, and total pretransplant sun burden were associated to the development of NMSC. In multivariate analysis, only skin type and total sun burden were independently related to NMSC. In conclusion, risk of posttransplant NMSC may be estimated combining skin type and an easy estimation of total sun burden. No individual immunosuppression regimen seems to be related to a higher risk of NMSC.