OBJECTIVES: To evaluate long-term cost-effectiveness of switching from human premix insulin to biphasic insulin aspart (BIAsp 30) in people with type 2 diabetes mellitus (T2DM) in China.  METHODS: The previously published and validated IMS Core Diabetes Model was used to project life expectancy, quality-adjusted life years (QALYs) and total direct medical costs over 30 years from a societal perspective. Patient characteristics and treatment effects were obtained from Chinese subgroup (n=1191) in the Achieve^® observational study. After treatment with BIAsp 30 over 24 weeks, patients’ HbA decreased by 1.6%, rate of major and minor hypoglycaemia decreased by 0.51 and 4.32 events per patient-year respectively. Treatment costs were based on insulin doses (35.8 IU daily for human premix insulin and 36.1 IU for BIAsp 30) and market retail prices in China. Management (concomitant medications, screening programmes, etc) and complication costs were obtained from Chinese published data in 2011 and adjusted to the price level of 2012 with the consumer price index. Costs and life years were discounted at 3% annually. One-way sensitivity analysis was performed. RESULTS: Switching to BIAsp 30 from human premix insulin was projected to reduce incidence of most diabetes-related complications, increase life expectancy by  0.732 years (13.457 vs 12.725 ) and improve quality-adjusted life years by 1.032 QALYs (9.487 vs 8.455) per patient. Although treatment and management costs increased by Chinese Yuan (CNY) 14,712 (52,329 vs. 37,617) and 1,857 (39,821vs. 37,964) respectively, complication costs reduced by CNY 96,198 (104,752 vs. 200,950); switching to BIAsp 30 from human premix insulin was associated with reduced total direct medical cost of CNY 79,628 (196,902 vs. 276,530). Sensitivity analyses demonstrated robustness of the results. CONCLUSIONS: Switching to BIAsp 30 from human premix insulin was associated with improvements in life expectancy and QALYs, and was a cost-saving treatment strategy for people with T2DM in China.