The Japanese Society for Bone and Mineral Research developed the Japanese Osteoporosis Quality of Life Questionnaire (JOQOL) to evaluate the disease-specific Health-Related QOL, which is specific for osteoporosis of Japanese patients. JOQOL was revised in 2000; it consisted of 38 items with the scale graded from 0 to 4 and a total full score of 152. To elucidate the reliability and validity of the revised JOQOL, we enrolled 193 postmenopausal women as subjects and diagnosed them as having osteoporosis or osteopenia. The mean age of the subjects was 68.2 +/- 8 years; 58 subjects (30.1%) had at least one vertebral fracture. Among them, 83 patients were retested for reliability. The mean lapse from the time of test to that of retest was 23.7(+/- 9.5) days. The subjects were questioned using the JOQOL, Medical Outcomes Study Short Form 36 (SF-36), along with questions on subjects' characteristics and their ADL. The JOQOL scores at the test and the retest were significantly correlated (r = 0.973) without significant difference between their mean scores. All the JOQOL items showed significant correlations at the test and the retest (Kendall's tau = 0.599-0.947). Cronbach's alpha coefficient of JOQOL was 0.918. These results proved the high reliability of JOQOL. The JOQOL score showed negative correlation with age (r = -0.183). The subjects with vertebral fractures had significantly lower JOQOL scores than the subjects without fractures. The JOQOL showed a significant correlation with all the scores in each domain of eight of SF-36 (r = 0.350-0.839). These results were consistent with that of the preceding study. It is concluded that the reliability and the validity of JOQOL were demonstrated in this study.