Prior research has shown that early life adversity is associated with physical health problems, but little is known about the health-related effects of coping in the context of having a parent with HIV/AIDS. The goal of this study was to investigate the associations between positive and negative coping strategies and diurnal cortisol among children affected by parental HIV/AIDS. Method: Participants were 645 children aged 8-15 affected by parental HIV/AIDS, who provided 4 saliva samples per day over 3 days (2 weekdays and 1 weekend day) to assess diurnal cortisol. Positive and negative coping strategies were measured via self-report prior to saliva collection. Possible confounds of the associations between coping and diurnal cortisol also were assessed, including age, gender, socioeconomic status, parenting quality, parental death, other stressful life events, sleep quality, and perceived health status. Results: Greater positive coping (e.g., problem solving, cognitive reframing) was associated with children's higher morning cortisol (p = .037), whereas greater negative coping (e.g., fighting, breaking things) was independently associated with lower morning cortisol (p = .038) and a flatter diurnal cortisol slope (p = .003). These associations remained significant after controlling for potential confounds. Neither positive coping nor negative coping interacted with stressful life circumstances to predict cortisol (all ps > .27). Conclusion: These findings indicate the extent to which a child's coping strategy is associated with indicators of stress biology in the context of having a parent with HIV/AIDS.