Background: We compared the efficacy and safety of insulin glulisine with insulin lispro as part of a basal-bolus regimen in children and adolescents with type 1 diabetes. Methods: Overall, 572 children and adolescents (4-17 years old) using insulin glargine or neutral protamine Hagedorn insulin as basal insulin were enrolled in a 26-week, multicenter, open, centrally randomized, parallelgroup, noninferiority study. Subjects were randomized to receive glulisine (n ¼ 277) or lispro (n ¼ 295) 0-15 min premeal. Results: Baseline-to-endpoint hemoglobin A1c changes were similar between the two insulins: adjusted mean change (glulisine vs. lispro), 0.10% versus 0.16%; between-treatment difference (glulisine-lispro), &minsu;0.06, 95% confidence interval (À0.24; 0.12); and prespecified noninferiority margin, 0.4%. Overall, for all age groups together, the percentage of patients achieving American Diabetes Association age-specific A1c targets at endpoint was significantly higher (P ¼ 0.039) with glulisine (38.4%) versus lispro (32.0%). From Month 4 to endpoint, both ''all'' and ''severe'' symptomatic hypoglycemia rates were similar (3.10 vs. 2.91 and 0.06 vs. 0.07 events/ patient-month, respectively). Frequency and type of adverse events, serious adverse events, or hypoglycemia reported as serious adverse events were similar between both groups. Conclusions: Glulisine was as effective as lispro in baseline-to-endpoint A1c change, and both treatments were similarly well tolerated.