This study was performed to investigate the effects of Acer tegmentosum Maxim. extract (ATE) on non-alcoholic fatty liver in Sprague Dawley (SD) rats. During oral administration of ATE, non-alcoholic fatty liver was induced by treatment with DL-ethionine. The lipid, total cholesterol (T-CHO) and malondialdehyde (MDA) in the liver tissue of ATE-fed rats showed lower levels, as compared to ATE-unfed rats. In ATE-fed rats, the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and γ-glutamyl transferase (GGT) were lower than the case of ATE-unfed rats. Oil red staining of the liver showed that the lipid deposits were decreased by feeding ATE. These results strongly indicated that ATE has positive effects of protection against non-alcoholic fatty liver formation.