Diabetes Mellitus (DM) is well known for increasing morbidity and mortality, especially related to their complications. The purpose of this study was to investigate the factors affecting the prevalence rate of DM and provide a fundamental material to develop an intervention strategy to reduce the prevalence rate of DM. The study subjects were adults aged over 19 on the basis of the primitive data of "The Fifth Korean National Health and Nutrition Examination Survey, 2012". Therefore, the data of 5995 participants were analyzed. For data process, the complex sample analysis module of SPSS 18.0 program was employed to add weighting before analysis. According to the analysis, the prevalence rate of DM of the study subjects was 10.5%. Regarding the odds ratio of DM prevalence, the subjects who graduated from middle school had the odds ratio 2.51 times higher than those who graduated from college and more; those in subjective bad health condition 4.77 times higher than those in subjective good health condition; those in obesity 1.44 times higher; those with high blood pressure 2.57 times higher; those with hyperlipidemia 2.63 times higher; those who fail to control their weight 1.31 times higher; those going on a diet 2.75 times higher. This study revealed that a level of education, perceived health status, obesity, high blood pressure, hyperlipidemia, weight control, and dietary therapy were the predictable variables of the prevalence rate of DM, and thereby suggested the nursing direction and research direction to reduce the prevalence rate of DM.