The hypovitaminosis D in the premenopausal women and the postmenopausal elderly women in Thailand was investigated. One hundred and six cases of the elderly women living in the urban area of Khon Kaen province, one hundred and thirty-two cases of the elderly women living in the rural area of Khon Kaen province, ninety-eight cases of the postmenopausal women who attended Menopausal Clinic, Srinagarind Hospital, Khon Kaen province, and 357 premenopausal women from the multicenters in Thailand were the subjects. The serum level of 25(OH)D < or = 35 ng/ml was used as the cut-off point of hypovitaminosis D. The prevalence of hypovitaminosis D in these selected groups of women was 65.4, 15.4, 60.2, and 77.8 percent respectively. The premenopausal female group had the highest prevalence of hypovitaminosis D and the lowest level of 25 (OH) D whereas the group of the postmenopausal elderly women in the rural area had the lowest prevalence of hypovitaminosis D and the highest 25 (OH) D level.