OBJECTIVE: To use experience sampling method (ESM) to examine the impact of inattentive and hyperactive-impulsive ADHD symptoms on emotional well-being, activities and distress, cognitive impairment, and social functioning assessed in the daily lives of young adults. The impact of subjective appraisals on their experiences is also examined. METHOD: Participants (n = 206) complete up to 56 in-the-moment assessments of mood and current activities using Personal Digital Assistants for 1 week. RESULTS: Multilevel modeling techniques reveal that ADHD inattentive and hyperactive-impulsive symptoms differentially relate to daily experiences. Higher inattentive symptoms are associated with indices of general distress, including less positive and more negative mood as well as more concentration problems. Higher hyperactive-impulsive symptoms are associated with reduced sensitivity to contextual factors in perceptions of situations. CONCLUSION: These findings demonstrate predictive validity for adult self-report of ADHD symptoms in a general population sample and suggest future research directions using ESM.