The relations between working conditions and various aspects of health among female hospital workers were studied in 26 departments of large hospitals in the Paris area in 1986; 90% of the workers of these departments filled in a questionnaire about their working conditions, sociodemographic characteristics and health in the previous 12 months and attended a medical examination. The study sample included 1505 women. The main cause of sick leave was musculoskeletal disorders and affected 16% of the women. Back pain was described by 47% of the women, and treatment for musculo-skeletal disorders by 28%. Three working conditions were considered to characterize the posture at work: standing more than six hours a day, bending over more than ten times per hour, and maintaining an uncomfortable posture. A cumulative posture index was constructed by adding for each worker the number of the working conditions to which she had been exposed. A cumulative lifting index was constructed in a similar way from the four following characteristics: lifting weights of more than 15 kg, lifting patients more than ten times a day, making beds normally or often, and pushing beds or trolleys more than ten minutes a day. A mixed index was then constructed associating the two previous ones. The relations between these indexes and musculoskeletal disorders (MSD) were studied after adjustment for potential confounders such as age, obesity, number of children, travel duration, sport practice, occupational level, number of years in the occupation, previous attack of back pain, and mental health (assessed by the score to the general health questionnaire). The logistic regressions of MSD indicators on the mixed index and other risk factors showed that MSD was about twice as frequent among women with a maximal load in posture and/or in lifting than among women with no more than one medium index (tiring posture or lifting). These facts support the necessity for improvement of the work load in hospitals.