A prospective non-randomized non-controlled multicenter trial has been conducted. The trial included 254 children, aged from 11 months to 18 years (mean age 9.3 +/- 4.5 years), with predominantly focal forms of epilepsy treated with trileptal (oxcarbazepine). The observation period was 31 weeks. Efficacy and safety of therapy was assessed in 3 visits: screening and assignment to therapy (visit 1), the end of titration and achievement of maintenance dose (visit 2), assessment of maintenance therapy (visit 3). The percentage of patients with a positive response to the trileptal therapy (the decrease of seizure frequency by 50% and more) was 91.1%. The complete reduction of seizures was achieved in 59.4% of patients. Most of patients (95.3%) continued to receive trileptal until the end of the trial. The significant decrease (p < 0.001) of seizure frequency from visit 1 to visit 3, the reduction of epileptiform activity (p < 0.05) on the awake EEG in visit 3 were found. The mean effective dose of trileptal was 902.4 +/- 442.7 mg/day, i.e. was less than 30 mg/kg/day, daily doses did not exceed 600 mg. Adverse effects were observed in 11.2% of patients but in 40% of cases they seemed not be related to the drug. The adverse effects were from mild to moderate extent. In conclusion, trileptal as the monotherapy is effective and well-tolerated in the treatment of focal epilepsies in the age groups studied.