In this population-based descriptive study covering the 65-year period, 1928-92, there was a 5-fold increase in hip fracture prevalence among Rochester, Minnesota residents between 1928-42 and 1973-82, from 135.8 to 675.8 per 100,000. This change was dictated almost entirely by an increase in the incidence of first hip fractures due to moderate trauma (n = 2058) that was observed among Rochester women through 1950, and among men through 1980, that affected all age groups. Declining incidence rates thereafter led to a 9% fall in hip fracture prevalence from 1973-82 to 1983-92 to a rate of 612.7 per 100,000. A 13.7-year increase in age at first hip fracture over the study period was accounted for by aging of the underlying population, and a comparable 13.9-year increase in the age at death following hip fracture appeared to result from improved survival in the population generally. Thus, trends in hip fracture prevalence were mainly determined by changes in incidence rather than relative changes in age at onset and death following hip fracture.