Objectives: This study was conducted in order to determine how the association between socioeconomic class and self-rated health among Korean aged 25-64 years. Methods: A nationally representative sample (1,875 men and 2,426 women) from the 2013 Korea National Health and Nutrition Surveys was analyzed. To estimate the odds ratio and 95% confidence intervals of self-rated health by socioeconomic class, logistic regression was conducted. Results: The study shows that socioeconomic class is related with self-rated health. that is, lower education and income led to a significant increase in poor health status. The odds ratio of self-rated health after controlling for age was 3.61 (95% CI, 2.02-6.47) for men, 3.07 (95% CI, 2.10-4.48) for women among those with the lowest-educated group compared to the highest-educated group. When equivalenced personal income was considered, the odds ratio of self-rated health for men was 2.25 (95% CI, 1.29-3.95), and 1.92 (95% CI, 1.30-2.83) for women among those in the lowest-income group compared to the highest-income group. Conclusions: This study finds out that there exist socioeconomic differences in poor health status in Korean. The effect of education is stronger than that of income for both men and women.