Background : Obesity, a global health problem and a chronic diseases, is associated with increased risk of developing type 2 diabetes and coronary heart diseases. A wide variety of natural remedies have been explored for their obesity treatment potential. To elucidate the anti-obesity effect of ginsenoside Rg5 : Rk1 (Rg5 : Rk1), a mixture of protopanaxadiol type ginsenosides isolated from Panax ginseng Meyer in a 3T3-L1 adipocytes. Methods and Results : In order to determinate the anti-obesity effect of Rg5 : Rk1, Oil Red O staining and triglyceride (TG) content was assessed. Furthermore, to elucidate the possible mechanism whether Rg5:Rk1 affects lipid accumulation, mRNA and protein expression analyses of adipocyte markers such as STAT3, PPARγ, CBEPα and ap2 were carried out. Rg5:Rk1 treatment showed an inhibition of lipid droplet accumulation and decrease on TG content. In addition, expression of STAT3, PPARγ, CEBPα and ap2 were decreased in dose dependent manner. Similar to these results, Rg5:Rk1 treatment reduced PPARγ and CEBPα protein expression. Conclusion : Rg5 : Rk1 treatment exhibits anti-adipogenic activity by down-regulation of the STAT3PPARγ/CEBPα pathway in 3T3-L1 adipocyte cell line.