Objectives This study is to investigate anti-obesity effects of Banggihwanggi-tang-hap-yeonggyechulgam-tang (BY), an herbal formula, in high fat diet induced obese mice model. Methods Fourty five male C57Bl/6J mice were randomly assigned to normal group fed with normal research diet (Nor, n=9), high fat diet control group treated with water (Veh, n=9), high fat diet group treated with orlistat (Oris; n=9, Orlistat 40 mg/kg), high fat diet group treated with low concentraion BY (BYL; n=6, BY 0.87 g/kg) and high fat diet group treated with high concentration BY (BYH; n=6, BY 1.74 g/kg). Results Seven weeks later, antioxidative capacity, body weight, epididymal fat pad and liver weight, reactive oxygen species (ROS), peroxynitrite ($ONOO^-$), alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol, triglyceride, high density lipoprotein (HDL), low density lipoprotein (LDL), superoxide dismutase (SOD), catalase, glutathione peroxidase (Gpx), heme oxygenase (HO)-1 and histology of liver were evaluated. In the BYH group, 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azinobis (3 ethybenzothiazoline-6-sulfonic acid) radical scavenging activity were more than L-ascorbic acid. Body weight gain were significantly less than Veh group. Epididymal fat pad and liver weight gain were significantly less than Veh group. ROS and $ONOO^-$ were significantly less than with Veh group. ALT and AST were significantly less than with Veh group. Total cholesterol, triglyceride and LDL were significantly less, HDL were significantly more than Veh group. SOD, catalase, Gpx, HO-1 significantly increased compared with Veh group. Injury on liver was lesser than Veh group. Conclusions It can be suggested that BY has anti-obesity effects in high fat diet induced obese mice model.