The effects of anxiety, depression and psychological stress on the secretion rate of salivary immunoglobulin (Ig)A were examined in a cross-sectional study of 114 registered nurses. A single, timed (five minutes) sample of whole unstimulated saliva was collected from each nurse; at the time of collection, psychosocial data for each nurse were collected by questionnaire. Nurses who reported more frequent episodes of anxiety had significantly lower mean secretion rates of salivary IgA than did nurses who reported only occasional episodes of anxiety. The concentration of secretory IgA in saliva decreased as the salivary volume increased. It was not possible to demonstrate whether anxiety influenced IgA secretion in saliva independently of its effects on salivary flow.