The present study was evaluated to determine if Cinnamaldehyde could attenuate HFD induced obesity in wistar rats through AMPK activation. The rats were randomly divided into five groups: Normal; HFD; Orlistat (OR) treated at 50mg/kg with HFD; Cinnamaldehyde (CA) treated at 40mg/kg and 80mg/kg with HFD. Western blot and RT PCR in white adipose tissue (WAT) was carried out. HFD treated group of rats stimulated lipid synthesis related genes like, PPAR-γ, aP2, ACC via inhibiting AMPK activation. CA and OR (standard anti-obesity drug) treatment showed up regulated the levels of pAMPK and its substrate pACC. AMPK signalling is responsible for the inhibition of adipocyte differentiation and fat accumulation. AMPK inhibit the activity of ACC through phosphorylation. mRNA expression of PPAR-α was up regulated in both CA and OR treated groups of rats. PPAR-γ, aP2, ACC mRNA expression were down regulated in both CA and OR treated rats in a dose dependent manner. These results suggest that CA ameliorates HFD induced obesity by down regulating the expression of lipogenesis related genes via AMPK activation in the WAT. Thus, these results provide molecular basis for the future research involved in the signalling pathways by which CA modulates lipid synthesis.