There are provided a method and device for transmitting/receiving reverse data rate information in a mobile communication system supporting multimedia service applications including voice and data services. According to the present invention, upon receipt of information about the maximum data rate of an SCH, a mobile station determines the minimum number of bits to be assigned to the reverse data rate information according to the number of data rates less than or equal to the maximum data rate and then transmits the reverse data rate information with the minimum number of bits to a base station.