The aim of this study was to follow up and assess QOL after THA. Fifty-six patients with coxarthritis were divided into three groups; group A comprising 26 unilateral coxarthritis patients, group B comprising 13 bilateral coxarthritis patients who underwent unilateral THA, and group C comprising 17 bilateral coxarthritis patients who underwent bilateral THA. Outcomes at 1,3, and 6 months after THA were measured with SF-36. In Groups A and C, SF-36 scores gradually improved at any point, while no improvement of the SF-36 scores were observed in group B. Group B scored significantly lower on all subscales of the SF-36 at 6 months than groups A and C. Our results suggest that patients with bilateral coxarthritis cannot expect much improvement of QOL after initial THA.