ObjectiveMethylphenidate is recommended as a first-line modality for treating attention deficit hyperactivity disorder (ADHD). In the past, immediate release methylphenidate (IR-MPH) was used for ADHD. Now oral osmotic-methylphenidate (OROS-MPH) is used for ADHD in China. This study was designed to investigate the efficacy and safety of OROS-MPH for treatment of ADHD in children. MethodsNinety-nine children with ADHD were randomly administered with OROS-MPH (18 mg/time, once daily) and IR-MPH (5 mg/ time, twice or three times per day). After 6 weeks of treatment, the therapeutic effects were evaluated by the SNAP-IV and the IVA-CPT. ResultsFifty patients completed the 6-week treatment. The effective rate (83.3% vs 75%) and the complete remission rate (44% vs 25%) in the OROS-MPH treatment group were higher than that in the IR-MPH treatment group. There were statistically significant differences in the SNAP-IV and IVA-CPT scores before and after treatment in the two groups (P＜0.01). The two groups had a similar incidence of side effects during treatment.ConclusionsOROS-MPH for the treatment of ADHD is effective and safe in children, and its once-daily administration is more convenient.