Purpose: The purpose of this study was to investigate the level of self management behavior of patients with type 2 diabetes and to compare the factors influencing self management behavior between the elderly and adults. Methods: The participants consisted of 105 adults and 100 elderly who visited the outpatient department of a hospital from August to December 2011. Data was collected by questionnaires and analyzed using the SPSS/WIN 18.0. Results: The elderly showed higher mean scores of subcategory of self management behavior than adults. In stepwise multiple regression analysis, a total of 42% (adults), 52% (elderly) respectively of variance in self management behavior were accounted for by self-efficacy, perceived barriers, perceived benefits, yes or no smoking and regular exercise in adults and readiness, self efficacy, perceived benefits in the elderly. Conclusion: Therefore, a diabetics intervention program should be designed and provided as a tailored one for adults and elderly separately in Korea. In the strategy for adults with type 2 diabetes in the promotion of self efficacy, perceived benefits and reduction of perceived barriers, and correction of life habits such as smoking and exercise are needed, whereas in the elderly promotion of readiness, self efficacy, perceived benefits are required.