A method for controlling transmission power in a mobile communication system is provided. According to the method, a serving base station arranges a plurality of terminals in ascending order according to Carrier-to-Interference-and-Noise-Ratios (CINRs) based on the CINR measured by the plurality of terminals, classifies the plurality of terminals in one of a first group and a second group according to the order, allocates a subchannel of a data region corresponding to the first group from among a plurality of data regions included in the uplink frame to a terminal classified as the first group, and allocates a subchannel of a data region corresponding to the second group from among the data regions to a terminal classified as the second group.