OBJECTIVE: An international literature review assessed the epidemiology, treatment patterns and cost associated with Attention Deficit/Hyperactivity Disorder (ADHD) in children. The objective of this abstract is to present the results on definition of the disorder, diagnosis, prevalence, demographics, age of onset and treatment guidelines, treatment in Europe. METHODS: The international literature search was complemented by country-specific literature searches in France, Germany, Italy, Netherlands, Spain and the UK. In each country a clinical expert was interviewed and reviewed the country-specific information. RESULTS: Across Europe, literature reflects the use of both the ICD-10 definition of Hyperkinetic Disorder (HD), and the DSM-IV definition of ADHD. In Italy the DSM-III and DSM-IIIR definitions are also reported. Diagnosis/ treatment initiation is usually made by child psychologists/psychiatrists and, increasingly, by paediatricians. Estimates of prevalence vary widely depending on the study population and diagnostic criteria used. For the general population, estimates based on the HD definition are in the range of 0.5-2.4% and those based on the ADHD definition are in the range of 5-10%. Reports from the UK and Germany indicated that features of the disorder arise before the age of 5 years. One source from Germany reported that symptom recognition occurred on average at 10.2 years of age, with 9.4% of the sample experiencing first symptoms at five years of age or younger. European treatment guidelines have been published and country specific treatment guidelines also exist in the UK, Netherlands, and Germany. Pharmacotherapy in Europe is primarily through the use of psychostimulants, although these are not generally available in Italy. CONCLUSION: The literature review established that ADHD/HD is a recognised disorder for children in Europe. Formal criteria are used to diagnose the disorder, studies have measured the prevalence, demographics, age of onset and treatment guidelines have been published.