Background: Obesity is known to influence on physical, mental, functional health problems but there have been no study of relationship between body mass index (BMI) and quality of life (QOL) in Korean elderly. Methods: A total of 216 elderly who had been attending two geriatric welfare facilities in Seoul answered the Korean version of obesity-related quality of life (KOQOL) questionnaire. Height, weight, waist circumference were measured. Body fat (%) was measured with HTM20 by impedance technique. Sociodemographic and medical factors were interviewed. QOL was assessed using KOQOL (ver.1) after excluding two sexual life related questions and one work related question. The total score is 48 points. The higher is the score, the poorer is the QOL. Results: In multivariable analysis, BMI, age, history of diabetes mellitus, history of osteoarthritis were associated with KOQOL score. Especially, BMI was significantly associated with KOQOL score after adjusting for waist circumference, body fat (%) (P = 0.002). Conclusion: The more BMI increases, the worse the obesity related QOL is in Korean ambulatory elderly.