In ADHD, impaired interpersonal relationships have been documented. They have been hypothesized to be secondary to impairment of receptive nonverbal language. Recognition of emotional facial expressions is an important aspect of receptive nonverbal language, and it has been demonstrated to be central to organization of emotional and social behavior. This study investigated the identification of facial expression of four emotions (joy, anger, disgust, and sadness) in a group of 30 children aged 7-12 years who met the DSM-IV criteria for ADHD disorder of the predominantly hyperactive-impulsive type and have no comorbid mental retardation, specific learning difficulties, developmental coordination disorder, pervasive developmental disorders, conduct disorder, bipolar disorder, or substance abuse, and in 30 matched unimpaired control children. The test used includes 16 validated photographs depicting these emotions in varying intensities constructed by morphing. Children with ADHD exhibited a general deficit in decoding emotional facial expressions, with specific deficit in identifying anger and sadness. Self-rating of the task difficulty revealed lack of awareness of decoding errors in the ADHD group as compared with control subjects. Within the ADHD group, there was a significant correlation between interpersonal problems and emotional facial expression decoding impairment, which was more marked for anger expressions. These results suggest suboptimal nonverbal decoding abilities in ADHD that may have important implications for therapy.