In order to determine UCP-2 mRNA levels in intraperitoneal adipose tissue of obese and no-obese humans and its role in the pathogenesis of obesity in humans, RT-PCR method was used for studying UCP-2 mRNA expression in intraperitoneal adipose tissue of 31 obese subjects (BMI > 25) and 34 no-obese subjects (BMI18.5-24). The results showed that compared with no-obese subjects, both male and female obese subjects displayed significantly lower average UCP-2 mRNA expression in the intraperitoneal adipose tissue (P < 0.05). It is concluded that UCP-2 may play a role in the pathophysiology of obesity.