The aim of the study was to establish the normative QUS data in a healthy sample of Croatian males and estimate the prevalence of osteoporosis. A total of 1002 male participants, aged 20-99, were recruited in seven study centers (Zagreb, Ivanić-grad, Koprivnica, Sibenik, Pula, Slavonski Brod, Vukovar). In each subject broadband ultrasound attenuation (BUA), speed of sound (SOS) and quantitative ultrasound index (QUI) of the calcaneus were measured using the Sahara ultrasound device. Significant declining with age was found for all three parameters (p < 0.001). The peak SOS (1562.8 +/- 28.5 m/s) and QUI (103.6 +/- 16.5) values were observed in the third decade, whereas the peak BUA value (86.2 +/- 19.2 db/MHz) was observed in the fourth decade of life. Using the World Health Organization diagnostic criteria for DXA the rates of osteoporosis in the males aged 50 and older were 5.8%, 3.4 and 4.2% for QUI, BUA, and SOS respectively. However, when we used the cut-off value of the T < or = -l.8, prevalence of osteoporosis in Croatian males older than 50 years was 16.2%, 11.7% and 17.2%.