The objective of the study was to investigate the effect of nobiletin on adipogenesis in 3T3-L1 cells. Here, we found that nobiletin could promote adipogenesis in 3T3-L1 cells in the absence of adipogenic inducers such as insulin, 3-Isobutyl-1-methylxanthine and dexamethasone. In addition, Real time quantitative PCR showed that the expression of adipogenic genes such as CCAAT/enhancer binding proteins, peroxisome proliferator-activated receptors-γ and fatty acid-binding protein aP2 were up-regulated in 3T3-L1 cells in the presence of nobiletin. Next, we investigated the role of Akt in the effect of nobiletin on the adipogenesis in 3T3-L1 cells by LY294002 blocking PI3K/Akt pathway. The experimental results showed that the promotive effect of nobiletin on adipogenesis was attenuated, accompanied by the down-regulation of adipogenic genes expression, after the activity of Akt was inhibited, suggesting that Akt plays an important role in the effect of nobiletin on promoting adipogenesis in 3T3-L1 cells. Still, the inhibition of Akt pathway by LY294002 was attenuated in the presence of nobiletin. These findings provide a possibility that nobiletin may be a potential candidate agent for stimulating Akt pathway in 3T3-L1 cells.