The objective of this study was to identify risk factors of metabolic syndrome in early adulthood which has currently shown an increase in Korea, due to a westernized lifestyle. Health medical examination data collected from a total of 5801 participants, gathered by the National Health Insurance Service(NHIS) in 2013, was used to proceed with the study. NCEP ATP-III was used as diagnostic criteria for determining metabolic syndrome. The prevalence rate for metabolic syndrome totaled 32.8%, 29.7% for men and 3.1% for women. Among the subjects, 21.5% of men were found to have abnormal waist circumferences compared to a percentage of 2.3% for women. However, the HDL-cholesterol levels for both men and women were very similar, at 13.6% and 13.3% respectively. There were statistically significant differences in their BMIs, family histories of diabetes, smoking periods, smoking frequencies, alcohol consumption, drinking frequencies, and intense physical activities for the metabolic syndrome group and the normal group. The factors influencing metabolic syndrome were BMI(OR=1.645, 95% CI, 1.599-1.692), a high risk of diabetes(OR=8.818, 95% CI, 4.493-17.306), drinking frequency(OR=1.151, 95% CI, 1.074-1.233), smoking period(OR=1.037, 95% CI, 1.010-1.064), whereas the family history of diabetes, smoking frequency, and physical activity showed no significance. The factors attributing to a high risk in diabetes were BMI(OR=1.021, 95% CI, 1.008-1.035), family history of diabetes(OR=1.835, 95% CI, 1.045-3.225), smoking period(OR=1.125, 95% CI, 1.050-1.206), presence of metabolic syndrome(OR=8.519, 95% CI, 4.876-14.885). The result from the data illustrates the necessity in developing programs and management education for such factors (BMI, smoking, drinking) that influence metabolic syndrome in early adulthood. Promotion of the environment and social awareness of metabolic syndrome is also required to make possible improvements in lifestyle.