The purpose of this study was to explore heterosocial relational outcomes in a college-aged sample showing symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD). Using questionnaires and a behavioral observation task, dating, sexual, and social outcomes were examined in three groups: 24 non-ADHD controls, 27 ADHD-Combined (ADHD/C) Type, and 13 ADHD-Primarily Inattentive (ADHD/IA) Type. The ADHD/IA group showed a consistent pattern of passivity and inexperience and was perceived relatively negatively by female confederates, whereas the ADHD/C group reported increased sexual drive and early dating experience. The effects of externalizing comorbidity differed by DSM-IV ADHD subtype. These findings indicate that ADHD-symptomatic adults differ by DSM-IV subtype in the manifestation of heterosocial deficits. Results suggest specific and divergent types of psychosocial intervention with ADHD/C versus ADHD/IA clients.