The adipose tissue is considered today as an endocrine organ in which tissue-specific regulation of gene expression plays a key role in the processes of development of obesity and comorbidities, such as diabetes and cardiovascular disease. The present study is focused on ITLN1, PPARã and TNFá gene expression in intra-abdominal adipose tissue and its effect on the serum levels of omentin 1 and TNFa in individuals with different body mass. It has been shown that serum TNFa level is significantly higher in the subgroup of patients with overweight and obesity (BMI ≥ 25 kg/m2) as compared to individuals with normal body weight (BMI < 25 kg/m2)( p < 0.03). We have demonstrated that the expression level of the PPARã gene is positively correlated with the ITLN1 gene expression level in the intra-abdominal adipose tissue (r = 0.516, p = 0.020). Serum level of omentin 1 positively correlates with PPARã mRNA and protein levels in intra-abdominal adipose tissue (r = 0.550, p < 0.05 and r = 0.581, p < 0.03, respectively). For the subgroup of patients with overweight and obesity, we have shown negative correlation of the level of TNFá mRNA with PPARã and ITLN1 mRNA levels was shown (r = –0.549, p < 0.05 and r = –0.475, p < 0.05, respectively). This study is the first to show a correlation relationship between PPARã gene expression level in the intra-abdominal adipose tissue and the expression and secretion levels of omentin 1.