The inhibitory effects of adipogenesis on ethyl acetate (EtOAc) fraction from leaves of the Tulip tree (TT) were evaluated. Exposure to TT EtOAc fraction (25~200 ${mu}g/mL$) for a 72 hr incubation period did not significantly change cell viability. TT EtOAc fraction, with concentrations of 100 and 200 ${mu}g/mL$, inhibited lipid accumulation in 3T3-L1 adipocytes in a dose dependent manner in adipogenesis. The expression of $PPAR{gamma}$ and $C/EBP{alpha}$, essential adipogenic markers, was significantly decreased when TT EtOAc fraction was added to cells for 8 days as compared with the untreated control group. These results suggest that TT EtOAc fraction might be a potential therapeutic agent as an effective, natural alternative material for obesity treatment.