Introduction: The most important risk factors for type II diabetic patients are poor nutrition, low physical activity, smoking and obesity indicating an inappropriate lifestyle. Objectives: This study aimed to investigate the factors affecting the health promoting lifestyle in type II diabetic patients compared with healthy people. Patients and Methods: The study was descriptive-analytic with two case-control groups carried out on 150 type II diabetic patients and 150 healthy people. Data were collected using demographic characteristics questionnaire and health promoting lifestyle profile II (HPLII). Results: There was a significant difference between the lifestyle of type II diabetic patients and healthy people (P<0.001). Additionally, there were significant differences regarding lifestyle dimensions between physical activity, nutrition and stress management in type II diabetic patients compared with healthy people (P<0.001). There was no significant difference between the two groups in the dimensions of spiritual growth (P=0.074), communication with others (P=0.363) and health responsibility (P=0.582). Conclusion: This study showed the effective role of lifestyle components in the development of type II diabetes. It is recommended to prevent or manage type II diabetes, through emphasizing on maintaining lifestyle and its dimensions.