Attention deficit-hyperactivity disorder (ADHD) is a problem of public health because of its frequency and impact. The objective of our work was to study the prevalence of ADHD in school population in the region of Sfax. Population and methods: The study was cross running from 1/4/2008 until 1/10/2008, caring on 513 students, 240 boys and 273 girls. They were enrolled in the first year of teaching basis until 5th year of basic education. Schools were randomly selected from a list provided by the Regional Directorate education in all schools of communal areas in the region of Sfax. The Conners scale of teachers and parents was used as a screening tool. Children who had at least one pathological test have benefited clinical evaluation with their parents. The diagnoses were according to DSM-IV-TR. Results The award of the Conners scale has identified 404 students for high scores were normal in the two versions of the scale for hyperactivity, impulsiveness and inattention, and 109 students who had a pathological score on at least one of the Conners scales. The interview with the 109 students, allowing clinical evaluation of children with reference to DSM-IV-TR, has enabled us to carry at least one diagnosis nosographic for 92 pupils of whom 51 had ADHD. Of a total of 513 students, 51 students were affected by ADHD DSM-IV. Thus, the prevalence of ADHD in schools in our study was 9.94%. In our study, ADHD was 5.26% in mixed-type cases, inattention prevalent in 2.7% and hyperactivity in impulsive 1.94% cases.