Abstract： Objective To evaluates the control of blood glucose in type 2 diabetes mellitus in large urban cities in China and further analyze the critical factors influencing medical cost Methods The data were collected from a sampling survey of patients with type 2 diabetes from 11 cities, including fasting plasma glucose (FPG) level, HbA1c, direct and indirect medical cost, and relevant contributing factors. Descriptive analysis was used to explore FPG and HbA1c data, the results were presented as percentage of patients with defined level of these parameters. The critical factors contributing to medical cost were analyzed with multifactor regression analysis model. Results Of the 1111 patients with type 2 diabetes mellitus, 296 were outpatients, 815 inpatients. FPG was not adequately controlled in 68% of these patients (>7.0 mmol/L). HbA1c was not adequately controlled in 42% of these patients (>7.5%). Multifactor analysis revealed that the significant factors influencing the medical cost of outpatients were the level of hospitals where patient are seen ( P <0.001), the presence of complications ( P <0.001) and FPG levels ( P <0.05). For inpatients, the medical cost was influenced significantly by days of hospital stay ( P <0.001), level of hospital, complications ( P <0 001) and family income per capita. Conclusion According to the treatment status in the year 2002, about 50% of the surveyed type 2 diabetic patients from large urban cities in China are not adequately controlled in terms of FPG and HbA1c. Complications and inadequate control of FPG (only outpatients) are significant factors contributing to higher medical cost of type 2 diabetes. This is further confirmed by multifactor analysis.