The purpose of this study is to verify the validity and reliability of the Attention Deficit Hyperactivity Disorder(ADHD) Scale. A sample of 642 participants, aged 12 to 68 years, whose schooling varied from 6 years of basic education to postgraduate studies. The Scale was composed by 115 items and distributed in 5 subscales: Attention Deficit, Hyperactivity, Impulsivity, Disruptive Behavior and Emotional Disturbs. The factorial analysis showed that a single factor could explain the variability of almost all results. The internal consistency coefficient was 0.95. In conclusion, this scale appeared to be a useful tool to make the diagnosis of ADHD in adolescent and adult life.