This study is an investigation into the epidemiologic and socioeconomic impact of osteoporosis-associated hip fractures in Austria. We determined age- and gender-specific incidence rates of osteoporosis-associated hip fractures for all patients treated in hospitals in 1995 and calculated mortality rates, hospitalization days and direct costs of hospitalization. The data were obtained from the hospital discharge statistics for all general hospitals and for all hospitals of the General Austrian Accident Insurance. To calculate the portion of hip fractures attributable to osteoporosis in a given age-group, a basic, non-osteoporotic incidence of hip fractures was determined for ages 20-39, using gender-specific regression models. 11,379 patients with osteoporotic hip fractures underwent treatment in Austrian hospitals in 1995, accounting for 79 percent of all hip fracture patients treated. 82 percent of those were female, with the highest incidence among women aged 95 years and older with a rate of 3,000/100,000. For male patients the highest incidence was observed for the age-group of 90-94 years with 1,743/100,000. International comparisons indicate these incidence rates to be similar to those reported for the Swiss population. In 1995, 778 patients or 6.8 percent of all patients with osteoporotic hip fractures died during hospitalization. Hospital care of patients with osteoporotic hip fractures required an overall 250,268 bed-days with an age-group-specific length of stay between 8.5-27 days for female and 16-23 days for male patients. The total cost of hospital treatment of osteoporotic hip fractures in Austria was ATS 1,043,379,000 (US$ 103,509,800), with average costs per patient of ATS 91,700 (US$ 9,097). Due to the aging of the population in the years to come, an increase of osteoporotic hip fractures among individuals aged 50 years and older must be expected. The economic importance of this development and its impact on the health care system must be considered as significant.