Diabetes mellitus is developed by lack of insulin secretion or reduction of tissues sensitivity to insulin, which lead to serious complications. The aim of this study is to evaluate antihyperlipidemic effect of betulinic acid (BA) on streptozotocin-nicotinamide (STZ-NA) induced diabetic mice. In this experimental study, seventy adult male NMRI mice (20-25 g) were divided randomly into seven groups (n = 10) of control, sham, diabetes, diabetes + BA (10, 20 and 40 mg/kg), and diabetes + metformin (200 mg/kg). Diabetes was induced by intraperitoneal (i.p.) injection of a single dose of STZ (50 mg/kg) 15 min after an i.p. administration of nicotinamide (NA) (120 mg/kg). BA and metformin were orally administered and after two weeks blood samples were taken. Blood levels of leptin, adiponectin, lipid profile and liver enzyme were then measured. One day after the last drug administration, liver was removed to evaluate the histological changes. A significant increase (P < 0.05) in the plasma levels of leptin, alanine-aminotransferase (ALT), aspartate-aminotransferase (AST), alkaline phosphatase (ALP), low density lipoprotein cholesterol (LDL-C), cholesterol, and a significant decrease in adiponectin and high density lipoprotein cholesterol (HDL-C) were observed in diabetic mice. The groups treated with BA indicated a significant decrease in leptin, AST, ALT, ALP, TG, cholesterol, LDL-C and an increases in adiponectin and HDL levels, while VLDL did not show significant changes. BA was found to have positive effects on liver injury. BA has an effective role on liver damage induced by diabetes through amelioration of leptin, adiponectin, liver enzyme levels and lipid profile. Since BA has a positive effect on lipid profile, adiponectin and leptin, it may improve metabolic syndrome.