A method and apparatus for establishing a RRC connection between a base station and a mobile station in a wireless communication system is provided. A packet transmission method for a communication system including a transmitter and a receiver according to the present invention includes transmitting, at the transmitter, a packet; retransmitting, when a confirmation message is not received in response to the packet, the packet; and stopping, when the confirmation message is received in response to the packet, retransmission of the packet. An RRC connection establishment method and apparatus of the present invention allows the transmitter to retransmit the RRC Connection Response message periodically until the RRC Connection Complete message is received from the receiver, thereby improving the RRC connection success probability.