Dispositional optimism, as a stable outcome expectancy, has been shown to predict health outcomes in several contexts. Research has demonstrated that health-impaired subjects with optimistic outlooks fared better than those with a pessimistic outlook. Choice of coping strategies has been theorized as the mediating factor through which optimism operates. However, the construct of dispositional optimism has been challenged as a polar opposite of neuroticism, thus contending that optimism is not an independent notion. The present study was designed to evaluate further the theoretical underpinnings of dispositional optimism theory. Subjects were selected from a population of cardiac patients who received an automatic implantable cardioverter defibrillator (AICD). This device, designed to save the patient from sudden cardiac death, dispenses an electric shock to the heart should it exhibit sustained ventricular tachycardia or fibrillation. This research project examined the relationship of dispositional optimism, coping, and neuroticism to psychological distress, life satisfaction, health perception, and frequency of prior AICD discharges. Intact data from 50 of the 60 participants were examined in multiple regression analyses. The results of the analyses were diverse. Principal findings were (a) general psychological distress was predicted solely by neuroticism but optimism predicted the majority of unique variance in the "style" with which subjects approach the assessment of distress; (b) optimism was subsumed under neuroticism in predicting health perception; (c) avoidance coping interacted with optimism in predicting a significant amount of unique variance over and above neuroticism in the number of AICD discharges experienced by the patients. In this latter finding, pessimistic patients who did not use avoidance coping received a greater number of discharges. Thus, optimism and neuroticism were not parallel constructs in all dependent variables. Also, the optimism/avoidance coping interaction in predicting an actual medical outcome was unprecedented. Limitations and directions for future research were discussed.