AIMS: To investigate the long-term efficacy and safety of empagliflozin as add-on to metformin in people with Type 2 diabetes. METHODS: Of 637 participants treated with empagliflozin 10 mg, empagliflozin 25 mg, or placebo once daily for 24 weeks, 463 (72.7%) were treated in a double-blind extension trial for ≥ 52 weeks. Prespecified exploratory endpoints included changes from baseline in HbA1c , weight and blood pressure at week 76. RESULTS: Compared with placebo, adjusted mean changes from baseline in HbA1c (overall baseline mean ± sd 63 ± 9 mmol/mol [7.9 ± 0.9%]) were -7 mmol/mol [(-0.6%) 95% CI -8, -5 mmol/mol (-0.8, -0.5%); P < 0.001] and -8 mmol/mol [(-0.7%) 95% CI -10, -6 mmol/mol (-0.9, -0.6%); P < 0.001], for empagliflozin 10 mg and 25 mg, respectively. Compared with placebo, adjusted mean changes from baseline in weight were -1.9 kg (95% CI -2.5, -1.3; P < 0.001) and -2.2 kg (95% CI -2.8, -1.6; P < 0.001) for empagliflozin 10 mg and 25 mg, respectively. Empagliflozin led to sustained reductions in systolic blood pressure vs. placebo. Adverse events were reported in 77.7, 80.2 and 72.0% of participants on placebo, empagliflozin 10 mg and empagliflozin 25 mg, respectively. Confirmed hypoglycaemic adverse events (glucose ≤ 3.9 mmol/l and/or event requiring assistance) were reported in 3.4, 4.1 and 4.2% of participants in these groups, respectively. CONCLUSIONS: In people with Type 2 diabetes, empagliflozin 10 mg and 25 mg given as add-on to metformin for 76 weeks were well tolerated and led to sustained reductions in HbA1c , weight and systolic blood pressure.