The forkhead transcription factor FoxO1 has been studied as the most downstream targets of the signaling pathway in mammals, and played a key role in adipogeneic, cell cycle progression, and energy metabolism and so on. The aim of this study was to investigate the tissue-specific and weight-dependent expression patterns of FoxO1 gene in porcine omental adipose tissue and its relation to adipose deposition. Sixty female Duroc × Landrace × Yorkshire pigs in 5 groups, each group containing twelve pigs weighing 1, 20, 40, 60, and 90 kg were used to study developmental expression of FoxO1 gene by means of semi-quantitative RT-PCR. The results showed that FoxO1 mRNA was expressed at a higher level in heart, brain, omental adipose tissue, skeletal muscle, liver and spleen, at a moderate level in kidney, lung, and peritoneal adipose tissue, and at a less level in duodenum, subcutaneous adipose tissue and pancreas. In addition, our data also showed that the expression levels of FoxO1 gene was lowest in the pigs at 20 kg, and continuously increased from 20 to 90 kg body weight (P<0.05). Furthermore, a close positive correlation between the expression levels of FoxO1 gene and the adipose deposition rate was found in pigs (r=0.84, P<0.05).