Peroxisome proliferator-activated receptor gamma (PPARgamma) participates in adipocyte differentiation and maintenance, including the promotion of lipid storage in mammals. In the present study, 3 duck PPARgamma small interfering RNA (siRNA) expression plasmids were constructed to investigate the effect of downregulating the expression of PPARgamma on adipogenesis and fat accumulation in ducks. The results indicate that the 3 siRNA specific for conserved regions of PPARgamma can effectively inhibit expression of PPARgamma. It was demonstrated that the expression of lipoprotein lipase and adipocyte fatty acid-binding protein in duck adipose tissue is repressed when the expression of PPARgamma is downregulated by siRNA. At the same time, the weight of abdominal fat at 21 and 35 d of age is decreased significantly (P < 0.05) compared with the control. However, the triglyceride levels in serum and muscle are not affected when the mRNA of PPARgamma is repressed. The current study indicates that the suppression of PPARgamma reduces abdominal fat deposition and regulates adipogenesis in ducks.