Work stress was assessed by continuous logging of heart rate in 31 air traffic control personnel at seven airports in Norway. The results showed work stress within reasonable limits in all categories of air traffic controllers. Tests of psychomotoric functions in 36 operators revealed that all categories of operative personnel, but the air traffic controllers especially, emphasized accuracy at the expense of speed. Measurements of blood pressure in nine of the 33 air traffic controllers who had shown significantly elevated blood pressure in 1981 during a serious labour conflict revealed values below what was to be expected for their age group.