Objective There are only limited data about the mortality of type 2 diabetes mellitus in Korea. We evaluated the mortality and cause of death in type 2 diabetes mellitus with prospective cohort of Korean type 2 Diabetes Mellitus. Methods Korea National Diabetes Prorgram (KNDP) is a multicenter large-scale prospective cohort study which began in 2005 and currently ongoing. This study analyzed the mortality, cause of death and risk factors of death using clinical data of patients whom were registered in KNDP cohort and cohort’s public health data(mortality data of the Statistics Korea (KOSTAT) and claim data of the Health Insurance review and Assessment Service(HIRA)of Korea (2006~2010)). We analyzed 4516 patients whose data is fully collected. Results The mean age of the patients was 58.3 ± 10.5 years and BMI was 25.2 ± 3.2 kg/㎡. Mean glycosylated hemoglobin level was 7.9 %, the mean duration of diabetes was 6.1 years. The follow up duration of cohort was 3.2 ± 1 years. The all-cause mortality rate (death per 1000 person-year) was 5.35 and the cardiovascular disease (CVD) mortality rate was 1.53, cancer mortality rate was 2.01. In patients without baseline cardiovascular disease or cancer, total mortality rate was 3.96, CVD mortality was 0.7, cancer mortality was 1.5. In the univariate analysis of the risk factors which was associated with the total mortality of patients without cardiovascular disease or cancer, age, diabetes duration, the use of insulin, and hypertension were shown to be significant, and in the multivariate analysis, age and use of insulin were the significant risk factor. Conclusion This study shows the first mortality data of Korean type 2 diabetes mellitus. Supported by further studies, we suggest that the strategy of the management of Korean type 2 diabetes mellitus might need some modification.