Objective: This study aims to explore the impact of differential degrees of obesity on health-related quality of life (HRQL) by sex in the Korean elderly. Method: We analyzed data on those aged between 65 and 74 years from the Korean National Health and Nutrition Examination Survey (KNHANES) using multiple regression analysis. Results: Compared with the lowest waist circumference (WC) quintile, the women in the fourth and fifth quintiles demonstrated significantly lower unadjusted HRQL but not the men in any quintiles. Whereas higher WC quintiles impaired mobility, usual activities, and pain/discomfort in women, the fourth WC quintile improved usual activities in men. After adjustment, only the women of the highest WC quintile reported impaired mobility. Discussion: Extreme obesity worsens mobility, and comorbidity in combination with obesity worsens HRQL in elderly women. Monitoring and controlling comorbidity and maintaining adequate WC decreases the risks of lowered HRQL in Korean elderly women.