The number of people with lifestyle-related diseases such as diabetes has been increasing every year due to our life styles today in Japan. This study discusses the behavioral changes of people with diabetes and the factors that cause the changes. It also discusses what directions successfully prompt the behavioral changes of those with Type- II diabetes. The following are the results of this study : 1. 14.5% of patients have changed their life styles regarding both diet and exercise, and 41.8%, either of the two, 2. more patients have changed their life styles regarding exercise than those regarding diet, 3. more patients who have a family history of diabetes have changed their behaviors than those with no diabetes family history, 4. the patients with more medical supervision are likely to change their life styles than those with less medical supervision, and 5. the survey on behavioral changes that we conducted has revealed that almost all the patients asked are willing to change their life styles.