['To examine the immune response to job strain and insecurity of 88 men working in a university, divided according to age and type of employment.', 'Anxiety, job strain, job insecurity and subjective symptoms were measured by questionnaires. Blood NK cytotoxic activity was determined by an in vitro method and lymphocyte subpopulations by flow-cytometry analysis.', 'Employees (over 40 years old) in a library showed higher values of job strain, anxiety and subjective symptoms and lower blood NK activity than the controls. The young employees with temporary employment showed high job insecurity and reduced blood NK activity, while the young sanitary staff with temporary position showed normal immune response. NK cytotoxic activity of the recruited men was negatively correlated with anxiety, work load and job insecurity.'] Is blood natural killer activity reduced in men with occupational stress and job insecurity working in a university?