There is considerable disagreement regarding whether defences operate unconsciouly, represent deliberate styles of coping with problems, or fall somewhere between. The present study considered the role of awareness in mediating the relation between defence and stress by establishing whether the conscious or unconscious nature of a given defence was associated with a distinct level of stress. The results forprojectionandrationalizationconfirmed the classical Freudian version of defence as an unconscious mechanism that reduces the stress of painful thoughts. Unconscious projectors and rationalizers reported singularly low levels of stress over the previous year.Repressionwithout awareness was associated with a distinctly high level of stress, whereasdenialwith awareness was related to lower stress. While these results provide some support for the view that defences must be unconscious to work effectively, they also suggest the diversity among defences in the role played by awareness in coping with stress.