A 5-year follow-up study investigated calcaneal bone mineral density (BMD) and changes in BMD in relation to fracture occurrence. The subjects comprised two cohorts born in 1914 and 1910 living in the city of Jyväskylä in central Finland. One hundred and three men (82%) and 188 women (73%), aged 75, and 57 men (74%) and 136 women (65%), aged 80, of the eligible population participated in the baseline bone measurements. The follow-up bone measurements were obtained for 59 men (68%) and 119 women (66%), aged 80 years, and for 21 men (53%) and 61 women (48%), aged 85 years. During the follow-up period, 8 men and 36 women from the younger and 11 men and 24 women from the older cohort sustained at least one fracture. When the baseline levels of BMD were related to fracture occurrence, the results clearly showed that with increased BMD values the probability of fracture decreased. Where men and women had similar BMD values, they also had a similar fracture probability. Except for one woman in the older cohort, none of those who had initial BMD values more than 1 standard deviation above the mean for their age developed a fracture during the follow-up period. The mean annual decrease in BMD was greater in the women (2.5-2.7%) than in the men (0.8-1.0%). The BMD change tended to associate with fracture occurrence only in the 75-year-old women (p = 0.075). The results suggest that calcaneus BMD can be used as a predictor of fracture occurrence in 75- to 80-year-old men and women. However, associating fractures with the change in BMD was difficult due to the limited number of survivors and initial differences in BMD values.