The present invention relates to process for preparing modified release pharmaceutical compositions of methylphenidate or salts thereof. In particular, the present invention relates to a modified release pharmaceutical compositions comprising at least one immediate release and at least one extended release component of methylphenidate or salts thereof. The composition may provide extended and specific release of methylphenidate or salts thereof to achieve therapeutically effective plasma concentration over a period of 12 hours to treat attention deficit disorders when administered to a patient in need thereof.
