Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by impaired insulin action and increased cardiometabolic risk. Visceral adiposity, insulin resistance, systemic inflammation, and dyslipidemia play key roles in the development of cardiovascular disease in individuals with T2DM. In this context, simple, rapid, and cost-effective biomarkers are increasingly important for risk assessment. The triglyceride-glucose (TyG) index is a practical indicator of insulin resistance, while the Atherogenic Plasma Index (API) reflects cardiovascular risk related to dyslipidemia. The Systemic Immune Inflammation Index (SII), derived from routine blood counts, serves as a marker of systemic inflammation. This study aims to evaluate the predictive value of TyG, API, and SII in assessing insulin resistance, cardiometabolic risk, and inflammation in patients with T2DM, thereby supporting early diagnosis and improved clinical management.