This study investigates how the interplay between adolescents' daily levels of emotional distress and diurnal cortisol relates to their risk-taking behaviors. Specifically, we test competing hypotheses whether emotional distress exacerbates the link between cortisol and risk taking, or whether cortisol only predicts risk taking in the absence of emotional distress. Ethnically diverse adolescents (N = 370; ages 11-18) reported their daily levels of emotional distress and risk-taking behavior for 5 days, and provided 4 saliva samples/day for 4 days. Emotional distress was positively associated with risk taking the same day and on average across days. Moreover, emotional distress and total cortisol output interactively predicted risk taking, such that total cortisol output was positively associated with risk taking on days when adolescents felt low levels of emotional distress, but not on days when adolescents felt high levels of emotional distress. High levels of emotional distress were associated with high levels of risk taking regardless of total cortisol output. There were no direct associations between cortisol and risk taking on daily or average levels. Results suggest that cortisol is associated with risk-taking behavior on days when adolescents are not already feeling emotionally distressed enough to take risks.