During periodic occupational medical checkup, in a sample including all employees from two high schools, a secondary school and a kindergarten, we administered through voluntary completion, questionnaires which assessed the employees’ occupational stress in terms of individual characteristics, anxiety, sense of self-efficacy, work ability, emotional exhaustion and health status (using ShortForm 36 questionnaire). A number of 233 questionnaires were returned. Only the occupational stressor represented by communication with superiors correlates significantly negatively with work ability in all four units. Work ability and communication with superiors also have average scores which differ significantly and are concordant in all four units. In the secondary school, work ability has the highest average value and the lowest average value of “communication with superiors” stressor. The same values are decreasing for WAI in order, from high school 2 to high school 1 and kindergarten while the stressor represented by communication with superiors has increasing values in order from high school no 2 to high school no. 1, and kindergarten. These results show that programmes to reduce occupational stress in school units should primarily address the school unit leadership in order to improve their communication with employees.