Here we report in vitro anti-adipogenic and antioxidant effects of Samchulgeonbi-tang (SCGBT), a traditional Korean herbal formula. 3T3-L1 preadipocytes were differentiated into adipocytes with or without SCGBT. After differentiation, we measured Oil Red O staining, glycerol-3-phosphate dehydrogenase (GPDH) activity and leptin production. In addition, its effect on scavenging activities of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radicals in in vitro systems. In differentiated 3T3-L1 adipocytes, SCGBT significantly inhibited lipid accumulation and triglyceride production, and mediated inactivation of GPDH, a major enzyme in the process of adipogenesis. Consistent with this, SCGBT stimulation significantly decreased the amount of leptin in 3T3-L1 adipose cells. Furthermore, SCGBT enhanced the scavenging activities on ABTS and DPPH radicals. The generation of malondialdehyde (MDA) during low-density lipoprotein (LDL) oxidation was significantly reduced by SCGBT treatment. Of interest, SCGBT extract inhibited reactive oxygen species (ROS) generation in 3T3-L1 adipocytes. Overall, our findings suggest that SCGBT has the potential for anti-adipogenic activity and antioxidant properties.