The purpose of this prospective study was to investigate the quantity and quality of bone by quantitative ultrasound (QUS) measurements and to assess bone resorption by urinary excretion measurement of C-terminal telopeptide of type I collagen (CTX) in an adult Turkish population living in an endemic fluorosis area and consuming drinking water with a high fluoride (F) concentration (mean 3.57 ppm F). Excretion of urinary CTX, heel broadband ultrasound attenuation (HBUA; dB/MHz), and speed of sound (SOS; m/s) were examined in 122 Turkish adults (37 pre-menopausal, 40 post-menopausal women, and 45 men) living in the endemic fluorosis area. For comparison, the same measurements were made on 117 controls (48 pre-menopausal women, 34 post-menopausal women, and 35 men) living in a nonendemic low F water area (mean 0.4 ppm F). In the F endemic area urinary excretion of CTX was higher in all subjects, whereas calcaneal BUA was lower in post-menopausal women. In the F endemic area SOS was significantly greater among pre-menopausal women but was not significantly different in the other two groups. Although non-trauma bone fracture rates were not significantly different among any of the groups, some of the bone marker differences indicate that exposure to prolonged high concentration of F may increase the risk of bone fracture, especially in post-menopausal women.