Objective: With the aim of getting more insight into compliance of children using methylphenidate, we studied the day-to-day use of the drug. In addition, the efficacy and side effects of treatment, stopping, switching to other drugs and the use of additional psychoactive drugs in daily practice were studied. Method: On the basis of pharmacy records, the use of methylphenidate by 52 children was studied. Two parameters for compliance were calculated. By means of a questionnaire, parents were asked about their children's compliance with the use of methylphenidate as well as about their experience with treatment. Main outcome measure: Compliance, use of methylphenidate in weekends and holidays, self-reported efficacy, side effects, stopping and switching to other drugs. Results: Depending on the parameter calculated, the percentage of children with a good compliance varied from 25 to 47%. About 65% of the children used less or no methylphenidate in the weekends and holidays. Sixty-five percent of the parents reported to pass over a dose once in a while. According to 61% of the parents (n = 28) the efficacy of methylphenidate was good or very good. Nine (33%) of 28 children stopped using methylphenidate. Seven children stopped using the drug because of side-effects or lack of efficacy. Seven children switched to other psychoactive drugs. Fifty-seven percent of all children used additional psychoactive drugs. Conclusion: The percentage of children having a good compliance calculated on the basis of pharmacy records is rather low. This is partly the result of the decreased use of methylphenidate in the weekends and holidays.