The aim of the survey was to describe the proportion of smokers and alcohol users in a group of children and adolescents admitted to a German department of child and adolescent psychiatry and psychotherapy. In addition, the proportion of smokers in this group of patients was compared with the proportion in the general population of the same age. The sample was composed of all children and adolescent inpatients (n=432, 8-17 years old meeting inclusion criteria) admitted to a German department of child and adolescent psychiatry between May 2001 and June 2003. A shortened adaptation of the questionnaire on legal and illegal drug use, developed by the Swiss Professional Service for Alcohol Problems, Lausanne, was used. Initiation, frequency and quantity of drug use, and parental substance use were assessed. The results showed an association between conduct disorder (CD) and attention-deficit/hyperactivity disorder (ADHD) and an early initiation of nicotine and alcohol use. Girls and boys with CD and ADHD were significantly more likely to be involved in higher levels of nicotine use compared with the general population. Parental nicotine use was associated with smoking in girls, while maternal nicotine use was associated with smoking in boys. Furthermore, regular alcohol use in both girls and boys was associated with nicotine use. To conclude, early initiation and elevated rates of nicotine and alcohol use are a particular risk for adolescents with CD and ADHD.