A method to transmit a packet of a BS in a communication system using a HARQ scheme is provided. The method includes assigning resource for transmitting a packet to a mobile station, and transmitting a first packet to the mobile station using the assigned resource; transmitting timing information on which a second packet is transmitted to the mobile station when the BS does not receive information indicating that the mobile station decoded the first packet successfully or when the BS receives information indicating that the mobile station failed to decode the first packet; and transmitting the second packet to the mobile station on a timing point corresponding to the timing information.