OBJECTIVES: Fatty liver disease is a potential long-term complication of liver transplantation (LT). We therefore aimed to determine the prevalence and risk factors of liver steatosis in a large population of adult post-LT patients. METHODS: We evaluated the clinical, biological, histological, and evolutive features of patients with a diagnosis of steatosis made at liver biopsy examination during post-LT follow-up. Risk factors were analyzed by univariate and multivariate analysis. RESULTS: In total, 1,596 liver biopsies from 599 patients were available. Recurrent liver disease was present in 178 patients. A histological diagnosis of steatosis was made in 131 (31.1%) of the remaining 421 patients (51.1% had normal liver tests): 53% had grade 1, 31% grade 2, and 16% grade 3 steatosis. Perisinusoidal fibrosis was present in 38 patients (29.0%). Histological lesions were consistent with the diagnosis of non-alcoholic steatohepatitis (NASH) in 5 patients (3.8%). At the end of follow-up, cirrhosis or extensive fibrosis was observed in 3 patients (2.25%). Multivariate analysis showed that seven factors (post-LT obesity, tacrolimus-based regimen, diabetes mellitus, hyperlipidemia, arterial hypertension, alcoholic cirrhosis as primary indication for LT, and pre-transplant liver graft steatosis) were risk factors for post-LT steatosis. When zero, one, two, three, four, five, and six factors were present, steatosis occurred in 6.0, 12.0, 22.1, 29.9, 65.5, 81.5, and 100.0%, respectively. CONCLUSIONS: Liver steatosis is a frequent late complication of LT; its development depends on a combination of host and graft factors. LT is therefore an interesting model to study the natural history and the determinants of liver steatosis.