Questionnaires assessing levels of job satisfaction and possible sources of stress were distributed to a random sample of general practitioners in the Greater Manchester area. The highest levels of job satisfaction were reported for ;intrinsic' job factors such as freedom to choose method of working, amount of responsibility and amount of variety, rather than ;extrinsic' factors such as rate of pay and hours of work. The main causes of stress appeared to be interruptions of various kinds. Factor analysis revealed four major sources of stress: interruptions; emotional involvement; administrative workload and work/home interface; and routine medical work. Of these, all but routine medical work were associated with job satisfaction. It is concluded that the major sources of stress for the general practitioner are not medical, but social.