Current theory suggests multiple pathways to the onset of Attention-Deficit/Hyperactivity Disorder (ADHD) and comorbid Oppositional Defiant Disorder or Conduct Disorder based on evidence of variation in the impairments observed within this population. The current study examined one proposed pathway to the onset of ADHD and comorbid disruptive behavior disorders in order to determine how low physiological arousal, as indicated by an atypical cortisol response to acute stress, may influence executive functioning. In order to understand the atypical response and to test the validity of this pathway, we tested the executive functioning of 75 children and adolescents (ages 10-15) who were previously diagnosed with ADHD+ODD, ADHD-only, or who were typically developing. Four executive functioning tests were completed before and after exposure to an acute stressor. Five saliva samples were also collected during the study, and cortisol values were obtained. No differences in executive functioning performance relative to the stressor were found. However, mothers? ratings of ADHD inattentive symptoms and aggression were predictive of cortisol as indicated by area under the curve with respect to ground. These findings provide some support for the theorized pathway and suggest a relationship between inattentive symptoms, aggression, and cortisol. Future research directions are suggested.