Aim: To compare the 2-h postprandial blood glucose (PPBG) excursion following a standard test meal in insulin-requiring patients with diabetes treated twice daily with human insulin mix 50 vs. insulin lispro mix 50 (LM50). Methods: This was a multicentre, randomised, open-label, crossover comparison of two insulin treatments for two 12-week treatment periods in 120 Chinese patients. One- and 2-h PPBG and excursion values were obtained following a standardised test meal. Fasting blood glucose (FBG), haemoglobin A1c (HbA1c), insulin dose, rate of hypoglycaemia and safety data were obtained. A crossover analysis using SAS Proc MIXED was employed. Results: Mean 2-h PPBG excursion decreased from 6.32 +/- 3.07 mmol/l at baseline to 3.47 +/- 2.97 mmol/l at end-point in the LM50 group, and from 6.31 +/- 2.88 at baseline to 5.02 +/- 3.32 mmol/l at end-point in the human insulin mix 50 group (p < 0.001). Two-hour PPBG (p = 0.004) and 1-h PPBG excursion (p < 0.001) were significantly lower with LM50 as compared with human insulin mix 50. Both treatment groups were equivalent for HbA1c control, 1-h PPBG and insulin dose requirements. Mean FBG was higher with LM50 than with human insulin mix 50 (p = 0.023). The overall incidence of treatment-emergent adverse events and hypoglycaemia rate per 30 days were similar between treatment groups. Conclusions: Insulin lispro mix 50 provided better postprandial glycaemic control compared with human insulin mix 50 while providing the convenience of injecting immediately before meals. Both treatments were generally well tolerated by all randomly assigned patients.