Little research on the prevalence and correlates of adult ADHD has been conducted outside the United States. The aim of the present study was to estimate the prevalence and correlates of adult ADHD in a large representative sample of the German population aged 18-64 years (n = 1,655). Two self-rating screening instruments to assess childhood and adult ADHD symptomatology were used to estimate the prevalence of ADHD. A 4-item screening tool was used to assess probable cases of current depression and anxiety (Patient Health Questionnaire). The estimated crude prevalence rate of current ADHD was 4.7%. Adult ADHD was significantly associated with lower age, low educational level, unemployment, marital status (never married and divorced), and rural residency. No association was found with gender. Adult ADHD was strongly associated with positive screening results for depression and anxiety. ADHD is a common disorder of adulthood, is associated with significant social impairment and psychiatric co-morbidity, and should receive further research attention.