Background: With the increasing frequency of body contouring surgery following weight loss, plastic surgeons have paid considerable attention to subcutaneous fat. However, few studies have investigated superficial and deep fat changes after bariatric surgery, and such studies have been limited to macroscopic assessments. The purpose of this study was to evaluate changes in superficial and deep fat in bariatric surgery patients using computed tomography (CT) to obtain quantitative measurements. Methods: This study included 11 patients (five males, six females; average age, 27 years) who underwent bariatric surgery at Dongsan Medical Center from October 2013 to October 2016. We excluded patients with a body mass index (BMI) <30 kg/m2 and those without both preoperative and postoperative CT images. We analyzed changes in subcutaneous fat area on CT images, with a mean follow-up of 5.5 months. We also performed a subgroup analysis using a BMI cutoff of 40 kg/m2. Results: Patients undergoing bariatric surgery showed significant reductions in weight, total fat, and the area of superficial and deep fat (P=0.002). In patients with a BMI less than 40 kg/m2, the reduction rate of superficial subcutaneous adipose tissue (sSAT) tended to be higher than that of deep subcutaneous adipose tissue (dSAT). Conversely, in patients with a BMI over 40 kg/m2, the reduction rate of dSAT was higher than that of sSAT. Conclusions We observed a difference in the reduction rate of sSAT and dSAT during weight loss after bariatric surgery, although it was not statistically significant. The reduction rates differed according to BMI.