Visceral fat is considered a key factor in the development of metabolic syndrome and other pathological conditions and diseases associated with obesity. Therefore, analysis of the dynamics of reducing the amount of abdominal visceral fat is important for evaluating the therapeutic effects of different modalities of obesity treatment, including bariatric surgery. In 53 obese patients visceral and subcutaneous abdominal adipose tissue was measured by ultrasonography (US) before and after bariatric surgery, in the period of 1, 3, 6 months. At the same time, standard anthropometric parameters were assessed: body mass (m), BMI, waist circumference (WC), and hip circumference (HC). Five diameters of the visceral abdominal fat (VAF) were measured: IAFT (Intraabdominal Fat Thickness), LV (Lienal Vein), VF (Visceral Fat), MES sum (Mesenterial leafs) and Max PFT (Maximal Preperitoneal Fat Thickness), and three diameters of the subcutaneous abdominal adipose tissue (SCAF): Min SFT (Minimal Subcutaneous Fat), and MaxSFTa and MaxSFTb (Maximal Subcutaneous Fat Thickness a and b). Statistically significant decrease in all anthropometric parameters, except HC was registered 1, 3 and 6 months after the surgery. We registered the decline of almost all US diameters of abdominal adipose tissue in the follow-up period, but statistically significant decrease were found only in the diameters of visceral adipose tissue: IAFT after 1 and 3 months (p = 0.031 and p = 0.027); VF after 1 month (p = 0.031), LV after 6 months (p = 0.011), and MESsum after 3 and 6 months (p = 0.001 and p = 0.028), as well as MaxSFTb, at 1 month follow-up (p = 0.015). In the short-term follow-up period after the bariatric surgery, there was a significant decrease in body mass, BMI and WC, and ultrasonography revealed a significant reduction in the diameters of the visceral abdominal fat.