Nonalcoholic fatty liver disease affects a substantial proportion of the general population worldwide. This high prevalence of nonalcoholic fatty liver disease has important consequences in the donor selection process for liver transplantation, and in the posttransplant period given the high recurrence rate of disease. This paper reviews the prevalence of nonalcoholic fatty liver disease, its progressive potential, and the implications of this liver condition in both the pre- and post-liver transplantation setting. Liver Transpl 12:523–534, 2006. © 2006 AASLD.