Whole native livers from orthotopic liver transplant (LT) recipients provide an ideal resource material for the proper identification and etiologic evaluation of end-stage liver diseases in these patients. This study determined the etiologic types of chronic liver disease (CLD) in adults of our geographic region receiving living donor LT and projected approximate estimates of their current prevalence and temporal changes in these in the general population. The final etiologic categorization of CLD in 372 adult LT recipients was made only after correlating the morphologic findings on explanted whole native livers with all pre-LT data and diagnosis. The final etiologic categorizations of end-stage CLD in the majority (88.4%) of explanted livers in our series were as follows: hepatitis virus related--48.6% [hepatitis C virus (HCV)--31.1%, hepatitis B virus (HBV)--15.9%, HCV and HBV--1.6%]; alcohol related--23.1%; and NALD related--16.7%. Of 84 cases clinically considered as cryptogenic cirrhosis, 57 and nine were finally categorized as nonalcoholic fatty liver disease (NAFLD) cirrhosis and noncirrhotic portal fibrosis, respectively. Hepatocellular carcinoma (HCC) was found in 20.7% of all livers, 81.8% of these tumors developing in HBV-related and/or HCV-related CLD and 9.1% each in alcohol-related and NAFLD-related CLD. The etiology of end-stage CLD in adults of our region has changed over time. HCV, more than HBV, is now the major cause of both CLD and HCC; alcohol-related CLD has increased significantly and several cases of cirrhosis clinically considered as cryptogenic, some of them with HCC, evolve from NAFLD. A proportion of cryptogenic cirrhosis cases that require LT are constituted by the noncirrhotic disease noncirrhotic portal fibrosis.