School nurses play an important role in the preventive health care of children and adolescents. This study aimed to describe and investigate the school nurses' different activities and time spent on these activities. By completion of a time study record form all 26 school nurses, in a medium-sized town in Sweden, documented their activities during 10 working-days. Altogether 635 record forms were received. It was found that almost half of the school nurses' time was used for individual pupil activities, 17% for groups of pupils and 34% for administrative activities. School nurses spent 17% of all their working time at the school clinic, which in some way may reflect the pupils need of the nurse in the school. These results highlighted the importance of school nurses and resulted in internal structural changes of school nurses' working time.