Background <p>Metabolic dysfunction-associated steatotic liver disease (MASLD) is common in patients with type 2 diabetes mellitus (T2DM). The triglyceride–glucose body mass index (TyG-BMI), which integrates insulin resistance and adiposity, may improve MASLD risk stratification, but evidence in hospitalized T2DM patients remains limited.</p> Methods <p>This hospital-based cross-sectional study included 324 hospitalized adults with T2DM. MASLD was assessed by abdominal ultrasonography. TyG-BMI was calculated as TyG index × BMI and compared with conventional metabolic indices using receiver operating characteristic analysis, multivariable logistic regression, spline modelling, reclassification metrics, subgroup and sensitivity analyses. Testosterone-related analyses were performed in male patients.</p> Results <p>MASLD was identified in 182 patients. TyG-BMI showed the highest discrimination for MASLD, with an area under the curve of 0.821 (95% CI: 0.775–0.866), outperforming TyG, BMI, atherogenic index of plasma, and hepatic steatosis index. The optimal cut-off was 227.22, with 75.1% sensitivity and 78.7% specificity. In the fully adjusted model, TyG-BMI remained independently associated with MASLD as a continuous variable and across quartiles; patients in the highest quartile had markedly higher odds of MASLD than those in the lowest quartile. TyG-BMI also improved reclassification beyond TyG alone. In men, testosterone was inversely correlated with TyG-BMI and showed a nonlinear association with MASLD risk.</p> Conclusions <p>TyG-BMI showed better non-invasive discrimination for MASLD than conventional metabolic indices in hospitalized patients with T2DM. As a readily available marker integrating insulin resistance and adiposity, TyG-BMI may be useful for first-line MASLD risk stratification in endocrinology inpatient settings. Testosterone-related findings in men were exploratory and warrant prospective validation.</p> Clinical trial number <p>Not applicable.</p>