To investigate the effects of 13 weeks treatment with empagliflozin in patients with high-risk type-2 diabetes mellitus on echocardiographic measures of left ventricular (LV) structure and function compared to placebo. A total of 91 patients were randomized to treatment with empagliflozin (25 mg/day, n = 45) or matching placebo (n = 45) for 13 weeks. Left ventricular (LV) mass, volumes and geometry as well as measures of LV systolic and diastolic function were measured using echocardiography at baseline and follow up. Mean LV mass index (LVMi) was reduced by - 11.5 g/m2 (95% CI - 56.4; 33.4, p = 0.03) with empagliflozin compared to - 1.4 g/m2 (95% CI - 36.5; 33.8, p = 0.63) for placebo. The proportion of patients with LV hypertrophy was reduced by 16.3% (p = 0.04) in the empagliflozin group compared to 1.1% in the placebo group (p = 1.00). The proportion of patients with left atrial volume index > 34 mL/m2 was reduced by 20.0% (p = 0.02) with empagliflozin compared to 9.5% for placebo (p = 0.45) and the E/e' ratio decreased (∆-0.8 (1.9) vs. ∆0.5 (2.0), p < 0.01). 13 weeks empagliflozin treatment in patients with type-2 diabetes at high CV risk significantly reduced LV mass, improved LV geometry and improved diastolic function compared to placebo.