A growing body of research suggesting a negative association between basal levels of cortisol and persistent antisocial behavior has emerged. The present study examined relations between awakening cortisol levels and antisocial trajectories from ages 5 to 15 years among individuals in the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development. Antisocial behavior was defined by semiparametric group modeling techniques, which revealed antisocial patterns parallel to Moffitt's (1993) taxonomy of antisocial trajectories. In contrast to the claim that biological diatheses are uniquely characteristic of individuals who demonstrate an early-onset pattern of antisocial behavior, our results suggest that individuals with elevated patterns of antisocial behavior between 5 and 15 years of age--irrespective of the timing of onset or desistance--are more likely to evidence lower awakening cortisol levels compared with individuals with persistently low levels of antisocial behavior. (Contains 1 figure, 1 table, and 2 footnotes.)