We sought to investigate the ability of biphasic insulin aspart 30 (BIAsp 30) to control postprandial hyperglycemia and hyperlipidemia in a meal-test comparison with biphasic human insulin 30 (BHI 30). In this randomised crossover trial, 50 patients with type 1 diabetes (mean age, 35.7 [plusmn] 9.4 years; body mass index [BMI], 24.0 [plusmn] 2.6 kg/m2; HbA1c, 8.6% [plusmn] 1.1%) were studied on 3 separate days, where the following treatments were given in random order: BIAsp 30 injected immediately before a standard breakfast, BHI 30 injected 30 minutes before breakfast (BHI 30t=[minus ]30), and BHI 30 injected immediately before breakfast (BHI 30t=0). The dose was 0.40 U/kg for all 3 treatments. BIAsp 30 reduced the area under the baseline adjusted 4-hour postprandial serum glucose curve (AUC0-4h) by 23% compared with BHI 30t=0 (P [lt ] .0001) and by 9% compared with BHI 30t=[minus ]30 (P = .013). Maximum serum glucose concentration (Cmax) was lower for BIAsp 30 compared with BHI 30t=0 (14.0 [plusmn] 2.4 v 16.5 [plusmn] 2.8 mmol/L, P [lt ] .0001), and time to maximal serum glucose concentration (tmax) was approximately 20 minutes shorter for BIAsp 30, irrespective of timing of BHI 30 injection (P [lt ] .0001). There were no significant differences among the 3 treatments with respect to postprandial levels of free fatty acids or triglycerides. The pharmacokinetic results were consistent with the above observations, ie, significantly larger insulin AUC0-4h, higher Cmax and shorter tmax were observed for BIAsp 30 compared with BHI 30, irrespective of timing of BHI 30 injection. We conclude that postprandial glycemic control was more effective with BIAsp 30 than with BHI 30, irrespective of timing of BHI 30 injection.