Abstract Introduction: Assessing the body composition is important in adult patients with type 2 diabetes mellitus to prevent and achieve optimum control during treatment. Bioelectrical impedance analysis (BIA), being a more affordable method of assessing the body composition, should therefore be compared with the gold standard dual-energy X-ray absorptiometry (DXA) to look for a correlation between the two and the potential of BIA to be used widely in this population. A cross-sectional observational study was conducted on 60 patients attending the endocrinology outpatient department (OPD) of a tertiary care centre in Kolkata, India. Methods: Body composition was measured by both BIA and DXA. Intra-class correlation (ICC) values were calculated between the two methods for fat mass and fat-free mass for three body mass index (BMI) groups and overall. Results: DXA and BIA correlated well for both fat mass and fat-free mass in the entire study population and in the non-overweight non-obese group (BMI <23) and the obese group (BMI ≥25). However, the overweight group (23 ≥BMI <25) did not correlate well with the above-mentioned parameters. Conclusion: We suggest interchangeable use of the two methods in the non-overweight non-obese (BM I <23) and obese (BMI ≥25) BMI groups of adult subjects with type 2 diabetes mellitus. However, the low correlation for all parameters in the overweight group points towards exercising caution when taking such measurements by BIA and planning a further study with a larger cohort of such individuals to better evaluate the said correlation.