A method of controlling a reverse data rate in a mobile station after receiving forward information commanding a reverse data rate change on a forward channel from a base station, the forward information commanding one of an increase, conditional increase, conditional decrease, and unconditional maintenance of the reverse data rate, the method comprising the steps of: if the received forward information commands a reverse data rate increase, increasing the reverse data rate to be equal to or lower than a maximum data rate, and determining whether the increased reverse data rate can be further increased for the next frame and transmitting the determination result with information representing the increased data rate to the base station; if the received forward information commands a conditional reverse data rate increase, increasing the reverse data rate to be equal to or lower than a maximum data rate based on information determined at the previous frame transmission indicating whether a data rate increase is available, and determining whether the increased reverse data rate can be further increased for the next frame and transmitting the determination result with information representing the increased data rate to the base station; if the received forward information commands a conditional data rate decrease, decreasing the reverse data rate to be equal to or higher than a minimum data rate based on information determined at the previous frame transmission indicating whether a data rate increase is available, and determining whether the decreased reverse data rate can be increased for the next frame and transmitting the determination result with information representing the decreased data rate to the base station; if the forward information commands an unconditional data rate maintenance, maintaining the reverse data rate, and determining whether the maintained reverse data rate can be increased for the next frame and transmitting the determination result with information representing the maintained data rate to the base station. if the received forward information commands a reverse data rate increase, increasing the reverse data rate to be equal to or lower than a maximum data rate, and determining whether the increased reverse data rate can be further increased for the next frame and transmitting the determination result with information representing the increased data rate to the base station; if the received forward information commands a conditional reverse data rate increase, increasing the reverse data rate to be equal to or lower than a maximum data rate based on information determined at the previous frame transmission indicating whether a data rate increase is available, and determining whether the increased reverse data rate can be further increased for the next frame and transmitting the determination result with information representing the increased data rate to the base station; if the received forward information commands a conditional data rate decrease, decreasing the reverse data rate to be equal to or higher than a minimum data rate based on information determined at the previous frame transmission indicating whether a data rate increase is available, and determining whether the decreased reverse data rate can be increased for the next frame and transmitting the determination result with information representing the decreased data rate to the base station; if the forward information commands an unconditional data rate maintenance, maintaining the reverse data rate, and determining whether the maintained reverse data rate can be increased for the next frame and transmitting the determination result with information representing the maintained data rate to the base station.