Purpose: Several health behavior factors affect the incidence of type 2 diabetes. Especially, obesity, which causes insulin resistance, is the most important determinant of diabetes. Therefore, we expect the risk factors associated with insulin resistance and type 2 diabetes are affected by obesity and, additionally, the related factors with diabetes caused by obesity can be controlled. Methods: This study used data collected from the 2001 Korea National Health and Nutrition Examination Survey (KNHANES). A stratified multistage probability sampling method was applied and the final sample included 5,500 subjects over 30 years old who had completed necessary health examinations and health behaviors survey. Results: The risk factors associated with type 2 diabetes are affected by obesity. According to logistic regression model stratified by body mass index (BMI) and sex, abdominal obesity and age were the significant risk factors of diabetes regardless of sex and BMI. However, drinking, smoking, total energy consumption, and protein consumption were risk factors for women with normal BMI, while carbohydrate consumption was a risk factor for man with normal BMI. Sleeping hours affected diabetes for women with obesity and fiber consumption was a risk factor for both women and men with obesity. In addition, statistically the family history of diabetes was a significant risk factor only in the group with normal weight, not in the group with obesity. Conclusion: The study results will provide information for implementing a regional initiative of type 2 diabetes prevention by BMI.