Defense mechanisms and coping strategies are discussed as two different types of adaptational processes. They may be clearly differentiated on the basis of the psychological processes involved, but not on the basis of their relation to outcome measures. Criteria that critically differentiate between defense and coping processes include the conscious/unconscious status and the intentional/nonintentional nature of the processes. Criteria based on the dispositional or situational status of the process, and on the conceptualization of the processes as hierarchical, are found to be more a matter of emphasis than of critical difference. A criterion that attempts to differentiate between defense and coping processes on the basis of their relation to psychological or physical health is found to be without support once the bias in self-report outcome measures is recognized.