The present invention relates to a solid oral modified-release composition comprising oxcarbazepine or salts thereof. In particular, the present invention relates to a solid oral modified-release composition comprising matrix of oxcarbazepine or salts thereof with one or more pharmaceutically acceptable excipients; wherein the composition is devoid of excipients having pH-dependent solubility. The invention further relates to a process of preparing such modified-release composition and its use in treatment of epileptic seizures.