Limited number of dual X-ray absorptiometry (DXA) devices in Croatia makes this diagnostic technique unavailable to the majority of the population. Quantitative ultrasound (QUS) of the calcaneus could be an alternative tool for assessing fracture risk. However, age-specific normative data should be obtained before using the QUS in everyday clinical practice. The aim of our Epidemiology of Calcaneus Ultrasound in Males (ECUM) study is to establish the normative QUS data in a healthy sample of Croatian males. A total of 1002 male participants, aged 20-99, recruited in different Croatian counties, were included in the study. In each subject broadband ultrasound attenuation (BUA), speed of sound (SOS) and quantitative ultrasound index (QUI) of the left calcaneus were measured using the Sahara ultrasound device (Hologic). The coefficients of variation were 2.85 for BUA, 0.37 for SOS and 2.49 for QUI. Significant declining with age was found for all three parameters, BUA (p<0.001), SOS (p<0.001) and QUI (p<0.001), with respective r values 0.14, 0.27 and 0.23. The peak SOS (1,562.8+/-28.5 m/sec) 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. A subgroup of 103 participants, aged 20-29, was used to estimate young adult mean and SD for QUI and calculate the T-scores. Using the World Health Organization diagnostic criteria the rates of osteoporosis (T-score<-2.5) in the males aged 50 and older was 5.8%. However, when we used the cut-off value of the T-score<-1.8, as previously suggested, prevalence of osteoporosis in Croatian males >50 yr was 16.2%. Although further studies might improve our understanding of the QUS role in the fracture prediction, we hope that the results presented here will improve the clinical management of osteoporosis in males.