OBJECTIVE: To compare blood glucose control and incidence of nocturnal hypoglycemia in adolescents with type 1 diabetes on multiple injection regimens managed with either an insulin analog combination or NPH insulin plus regular human insulin. RESEARCH DESIGN AND METHODS: In a randomized cross-over study, 28 adolescents with type 1 diabetes on multiple injection therapy received either insulin glargine prebedtime plus lispro preprandially (LIS/GLAR) or NPH insulin prebedtime plus regular human insulin preprandially (R/NPH). During each 16-week treatment arm, subjects completed home blood glucose profiles, and at the end of each treatment arm, they were admitted for an overnight metabolic profile. A total of 25 subjects completed the study. RESULTS: Compared with R/NPH therapy, LIS/GLAR was associated with lower mean blood glucose levels (LIS/GLAR versus R/NPH): fasting (8.0 vs. 9.2 mmol/l, P < 0.0001), 2 h postbreakfast (8.1 vs. 10.7 mmol/l, P < 0.0005), prelunch (8.9 vs. 10.1 mmol/l, P < 0.01), and 2 h postlunch (8.0 vs. 9.5 mmol/l, P < 0.002). However, there was no difference in mean blood glucose levels before or after the evening meal. Incidence of nocturnal hypoglycemia on overnight profiles was 43% lower on LIS/GLAR compared with R/NPH therapy; however, there was no difference in rates of self-reported symptomatic hypoglycemia. Total insulin dose required to achieve target blood glucose control was lower on LIS/GLAR (1.16 IU/kg) compared with R/NPH therapy (1.26 IU/kg, P < 0.005), but there was no significant difference in HbA(1c) levels (LIS/GLAR versus R/NPH: 8.7 vs. 9.1%, P = 0.13). CONCLUSIONS: Combination therapy with insulin glargine plus lispro reduced the incidence of nocturnal hypoglycemia and was at least as effective as R/NPH insulin therapy in maintaining glycemic control in adolescents on multiple injection regimens.