Objective: Individuals with ADHD often report sleep problems. Though most studies on ADHD and sleep examined children or nonclinically diagnosed adults, the present study specifically examines nonmedicated adults with ADHD to determine whether inattentive and hyperactive-impulsive symptoms are associated with sleep problems. Method: A total of 22 nonmedicated adults diagnosed with ADHD are assessed with a "DSM-IV"-based interview and the Pittsburg Sleep Quality Index (PSQI). Results: The number of hyperactive-impulsive symptoms indicate a positive correlation with sleep duration, habitual sleep efficiency, and global PSQI score. No significant associations are found between inattentive symptoms and sleep quality. Conclusion: The results show that sleep problems are associated with hyperactive and impulsive symptoms in nonmedicated adults with ADHD. These findings provide information on the nature of sleep problems without the confounding effects of medication associated with ADHD. Treatment of sleep problems, especially in those with hyperactive-impulsive symptoms, may help ameliorate ADHD symptomatology. (Contains 1 table and 1 figure.)