Purpose: The purpose of this study was to investigate the level of self management of patients with poorly controlled type 2 diabetes, and to investigate the factors influencing self management. Methods: The subjects consisted of 117 diabetes patients who visited the outpatient department of a university hospital from March to August 2008. Data were collected by asking the subjects to answer a 54-item questionnaire and were analyzed using the SPSS/WIN 14.0 program. Results: The total mean score of the patients in self -management was 4.38 out of 7. Medication adherence obtained the highest score under self-management, and the self-monitoring of blood glucose obtained the lowest score. Family support, self-efficacy, severity, and depression were found to be significantly correlated with self-management. In stepwise multiple regression analysis a total of 44.5% of the variance in self management was accounted for by family support, self-efficacy, severity, and depression. Conclusion: Therefore, a diabetic intervention program should be designed and provided for increasing family support, self efficacy, and severity and for reducing depression of patients with poorly controlled type 2 diabetes.