Attention deficit/hyperactivity disorder (ADHD) is a pathology characterized by inattention, hyperactivity and impulsivity. The purpose of this article is to conduct an epidemiological study on symptoms of ADHA and behavior disorders in public schools of Florianopolis/SC. The study involved 1,898 students (1,001 males and 897 females) enrolled in five public schools of Florianopolis, from the 1st up to the 4th grades, aged 6 to 12. The instrument used was the EDAH, filled out by teachers and parents, which classifies children with predominance of the following symptoms: hyperactivity, attention deficit, conduct disorder, hyperactivity with attention deficit and ADHD associated with conduct disorder (global). Of the 1,898 students, 95 (5%) showed symptoms of ADHA associated with behavioral disorders. Regarding gender, the prevalence was higher in boys, in a 3:1 ratio. Our data is in accordance with the literature. The distribution of the ADHD subtypes by gender is similar to the mentioned literature.