One third of the world's hip fractures are said to occur in Asia, mostly in China. However, there have as yet been no validated studies of hip fracture rates in China. The authors estimated the incidence of hip fractures in Beijing, People's Republic of China, and took several steps to validate the estimates. All 76 Beijing hospitals reported all 1988-1992 admissions that had been coded as 820 (hip fracture) or 821 (other femoral fracture) according to the International Classification of Diseases, Ninth Revision. The authors then compared a random sample of the reports with original medical records, and discovered that 70% of intertrochanteric hip fractures had been miscoded as "other femoral fractures." The authors retrained all hospital staffs to provide corrected reports. Revised reports missed only 13% of the hip fracture cases recorded in operating room logs of 11 randomly selected hospitals. To validate hospital-based estimates of hip fracture rates, the authors interviewed a random sample of 2,113 Beijing women aged 50 years or more (97% response rate); all but 4% of past fractures and all seven hip fractures had been treated in hospitals. Finally, the authors surveyed the 27 hospitals in the counties surrounding Beijing. No Beijing residents had been treated for hip fracture outside of the city. Based on the 1990 China census, age-standardized rates of hip fracture (per 100,000) in Beijing-87 for women, 97 for men-were much lower than those seen in Hong Kong in 1985 (353 for women, 181 for men) or in US Caucasians (510-559 for women, 174-207 for men). From 1988 to 1992, the rates in Beijing increased 34% in women and 33% in men. The authors conclude that hip fracture rates in Beijing are among the lowest in the world but may be rising rapidly.