Objective <p>We aimed to investigate the association between insulin resistance and abdominal adiposity, focusing on the relative contributions of visceral and subcutaneous adipose tissue as assessed by cross-sectional computed tomography (CT) imaging.</p> Methods <p>In this retrospective study conducted between January and July 2023, we analyzed data from 81 patients diagnosed with type 2 diabetes and 44 healthy controls. Each participant had undergone thoracoabdominal CT imaging, and their relevant blood tests for triglycerides, glucose, and HDL-C were obtained simultaneously with the imaging to ensure the contemporaneity of both datasets. Radiologic measurements were made at the level of the first abdominal slice (segment 1) and L1-2 vertebra (segment 2) where the lung tissue ends.</p> Results <p>Total adipose tissue (TAT), visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) volumes were significantly higher in diabetic patients compared to controls (all <i>p</i> &lt; 0.001). In contrast, there was no significant difference in age (<i>p</i> = 0.114) or gender distribution (<i>p</i> = 0.382) between the groups. The TyG index and TG/HDL-C ratio, which are validated surrogate markers of insulin resistance, were significantly elevated in the diabetic group (<i>p</i> &lt; 0.001). Receiver operating characteristic (ROC) analysis demonstrated that VAT in the second segment had the highest discriminatory ability for predicting diabetes (AUC 0.855, 95% CI 0.789–0.921), with an optimal cutoff value of 11.69 cm² yielding a sensitivity of 85.0% and specificity of 71.1%. In the multivariate analysis, only VAT in the second segment remained independently significant (<i>p</i> &lt; 0.001) for differentiating diabetic and non-diabetic individuals. VAT also showed a moderate positive correlation with the TyG index and TG/HDL-C ratio, reflecting its strong link with insulin resistance, while no significant correlation was found between SAT and these metabolic markers.</p> Conclusion <p>This study underscores the pivotal role of visceral adipose tissue in the development of insulin resistance in patients with type 2 diabetes, highlighting its greater impact compared to subcutaneous fat. CT imaging allowed for quantitative evaluation of abdominal fat compartments, revealing meaningful associations with surrogate insulin resistance markers. However, its feasibility in routine clinical practice is limited due to radiation exposure and the retrospective nature of this study. Future research should validate these findings through larger prospective cohorts and explore less invasive imaging modalities.</p>