Abstract： Objective To investigate the in patient costs change in diabetic patients during 1995～1999.Methods According to ICD 9 code and the standard forms for the investigation of medical expenditure, all the patients with diabetes were analysed for their hospital costs.Results 948 cases (1509 admissions) with diabetes were used for the analysis. The average total cost was 2382 RMB yuan, including 950 for the drugs, 621 for the examinations, 524 for the bedding and nursing in 1995, and was increased annually to total 4850 RMB yuan with 1734 for the drugs, 1198 for the examinations, 1564 for the bedding and nursing in 1999 respectively, which means 103 7%,82 5%,92 9% and 198 5% increases respectively. The hospitalied length was decreased from 24 6 in 1995 to 22 6 days in 1999. These diabetic patients with cerebral infarction, hypertension, cholecystitis and/or gallstones,and upper respiratory infection, spent 2 02?1 89?1 32?3 70 times more money than their counterparts without diabetes (4390 vs 2175, 3560 vs 1887, 4103 vs 3102, 2285 vs 618 RMB yuan, P<0 01).Conclusion The in patient medical costs for diabetic patients dramatically increased in last 5 years. The diabetic patients admitted for other diseases cost much more than their counterparts without diabetes.The health economics in diabetes should been paid more attentively, particularly in China which has the biggest diabetic population and is a developing country.