Recent investigations of possible associations between attention deficit hyperactivity disorder (ADHD) and substance-use disorders are reviewed. ADHD seems to represent a possible risk factor for developing a substance abuse, up to 50% of patients with on continuing ADHD symptoms from childhood were found to develop a substance-use disorder. Based on possible pathophysiological similarities, especially cocaine and nicotine dependence are of focused interest in adolescents and adults with ADHD. The presence of ADHD may influence adolescent and adult substance-use disorders in different ways: earlier age of onset, higher frequency, longer duration of substance abuse and transition from alcohol-abuse to other substance-use disorders. Possible pharmacological and non-pharmacological therapeutic strategies in patients with ADHD and substance abuse are discussed.