It is still controversial whether type 2 diabetes mellitus (T2DM) is associated with increased left ventricular (LV) mass independent of body size. We tested the hypothesis that T2DM is independently associated with LV mass in a multiethnic cohort. In the Northern Manhattan Study (NOMAS) cohort sample, a total of 1,932 subjects (67.9 ± 9.6 years, 769 men and 1,163 women, 443 with DM and 1,489 without DM) were studied by transthoracic echocardiography, and LV mass was calculated. LV hypertrophy was defined as the upper quartile of LV mass. Multivariable models were used to assess the association of T2DM with LV mass after adjusting for age, gender, race, body mass index (BMI), systolic blood pressure, education, history of coronary artery disease, physical activity, and alcohol consumption. LV mass (189 ± 60 vs 174 ± 59 g, p <0.0001), BMI, and systolic blood pressure were higher in the DM group than in the non-DM group, whereas age and gender distributions were similar between groups. In multivariable analysis, T2DM was independently associated with increased LV mass (p = 0.03). Presence of T2DM was associated with increased risk of LV hypertrophy (adjusted odds ratio 1.46, 95% confidence interval 1.13 to 1.88, p = 0.004). Although no interactions were observed between T2DM and BMI on LV hypertrophy (p = 0.6), there was a significant interaction between T2DM and waist circumference on LV hypertrophy (p = 0.01). In conclusion, T2DM was independently associated with increased LV hypertrophy independent of various covariates in this multiethnic sample. Presence of T2DM increased the risk of LV hypertrophy by about 1.5-fold, and it possibly interacted with central obesity.