The authors present the results of the treatment with methylphenidate in 24 children with attention deficit disorder based on DSM-III. The prescribed dose was 5 to 10 mg per day, once or twice a day. The results were good in 79.1% of the patients and poor in 16.6%. The drug was withdrawn in one patient because of side effects and the evaluation of efficacy was not possible. Side effects occurred in 2 children (headache and/or nausea). The therapeutic response and the side effects are compared with the literature. The authors claim attention to the efficacy and safety of the treatment with methylphenidate.5425-9