In a case-control study, the relationship between sporting activities and osteoarthrosis of the hip in women was investigated. The study base comprised Swedish women 50 to 70 years of age between 1991 and 1994. Case subjects (N = 230) had had total hip replacements because of primary osteoarthrosis of the hip, and control subjects (N = 273) were randomly selected women without hip problems from the study base. All women were interviewed about sports activities to the age of 50, health status, smoking habits, occupational history, and work in the home. Three exposure classes were defined based on total hours of sports activities aggregated to the age of 50. The relative risks of developing osteoarthrosis of the hip leading to total hip replacement was 2.3 (confidence interval, 1.5 to 3.7) for those with high sports exposure and 1.5 (0.9 to 2.5) for those with medium sports exposure compared with those with low exposure. The relative risks were adjusted for age, occupational physical load, body mass index, hormone therapy, and smoking. Physical load from sporting activities seems to be a moderate risk factor for women for the development of severe osteoarthrosis of the hip. Participation in sports was low, and therefore individual risk estimates for different sports activities were not possible to obtain.