OBJECTIVES: To evaluate long-term cost-effectiveness of switching to biphasic human insulin 30 [Isophane Protamine Biosynthetic Human Insulin Injection (pre-mixed30R)] in people with type 2 diabetes (T2DM) poorly controlled with oral antidiabetic drugs (OAD) in China. METHODS: The validated IMS CORE Diabetes Model (V8.5) was used to project long-term life years, quality-adjusted life years (QALYs) and costs over 30 years. Patients’ baseline demographics and treatment effects were based on the published 8-week observational study in China .Hba1c deceased from 10.18% to 7.57 after initiating biphasic human insulin 30 (±metformin) for people uncontrolled with sulfonylureas and metformin, and hypoglycaemic events was 0.80 per patient-year during the study period. Treatment costs were calculated by multiplying retail prices in China and dosage used in the trial. Management and complication costs were obtained from published data in 2011 and inflated to 2012 with consumer price index. An annual discounting rate of 3% was used for both costs and health outcomes. One-way sensitivity analyses were conducted. RESULTS: It was projected switching to biphasic human insulin 30 improved life expectancy by 0.655 years (13.113 vs. 12.458) and quality-adjusted life-years by 0.609QALYs (9.270vs. 8.661) per patient. Biphasic human insulin 30 decreased cumulative incidence of most diabetes-related complications, and was associated with decreased management and complication costs of -6787 RMB (147066 vs. 153853).Although offset by higher direct treatment cost (54671 vs. 54366), switching to biphasic human insulin 30 was projected to lower total direct medical cost of -6482 RMB lower (201737 vs. 208219). Sensitivity analyses demonstrate robustness of result. CONCLUSIONS: Initiating biphasic human insulin 30 for OAD failures was projected to improve life expectancy and reduce lifetime direct medical costs. Switching to biphasic human insulin 30 was a cost-saving treatment option for people with T2DM insufficiently controlled with OADs in China.