OBJECTIVE: To compare the efficacy and safety of new insulin glargine 300 units/mL (Gla-300) with glargine 100 units/mL (Gla-100) in people with type 2 diabetes using basal insulin (≥42 units/day) plus oral antihyperglycemic drugs (OADs). RESEARCH DESIGN AND METHODS: EDITION 2 was a multicenter, open-label, two-arm study. Adults receiving basal insulin plus OADs were randomized to Gla-300 or Gla-100 once daily for 6 months. The primary end point was change in HbA1c. The main secondary end point was percentage of participants with one or more nocturnal confirmed (≤3.9 mmol/L [≤70 mg/dL]) or severe hypoglycemic events from week 9 to month 6. RESULTS: Randomized participants (n = 811) had a mean (SD) HbA₁c of 8.24% (0.82) and BMI of 34.8 kg/m(2) (6.4). Glycemic control improved similarly with both basal insulins; least squares mean (SD) reduction from baseline was -0.57% (0.09) for Gla-300 and -0.56% (0.09) for Gla-100 (mean difference -0.01% [95% CI -0.14 to 0.12]), with 10% higher dose of Gla-300. Less nocturnal confirmed (≤3.9 mmol/L [≤70 mg/dL]) or severe hypoglycemia was observed with Gla-300 from week 9 to month 6 (relative risk 0.77 [95% CI 0.61-0.99]; P = 0.038) and during the first 8 weeks. Fewer nocturnal and any time (24 h) hypoglycemic events were reported during the entire 6-month period. Weight gain was lower with Gla-300 than with Gla-100 (P = 0.015). No between-treatment differences in safety parameters were identified. CONCLUSIONS: Gla-300 was as effective as Gla-100 and associated with a lower risk of hypoglycemia during the night and at any time of the day.