Provided are a sustained-release composition including pregabalin and a pharmaceutically acceptable salt thereof using a gastroretentive drug delivery system (GRDDS), an oral sustained-release formulation using the composition, and a preparation method thereof. In a sustained-release composition according to the present invention and a formulation including the same, a coating compartment including a sugar or a derivative thereof and a plasticizer is introduced onto the outer surface of pregabalin having a less stable structure to ensure stability and to improve compatibility with excipients at the same time, and also to effectively control the release rate. As a result, dosing convenience is improved to provide a gastroretentive drug delivery system having enhanced patient compliance. Therefore, the present invention may exhibit improved therapeutic or prophylactic effects on various neurological diseases, such as neuropathic pain, epilepsy, fibromyalgia syndrome, etc., which have not been easily accomplished due to the characteristics of pregabalin.
