The present invention relates to a wireless access system supporting machine-type communication (MTC), and more specifically, to methods for controlling uplink transmission power by an MTC terminal and apparatuses supporting same. A method for controlling uplink transmission power by an MTC terminal in a wireless access system supporting machine-type communication (MTC), according to one embodiment of the present invention, comprises the steps of: repeatedly receiving, a specific number of times, a first downlink control channel including a first transmission power command (TPC); transmitting, a specific number of times, a first uplink channel according to the transmission power indicated by the first TPC; and receiving a second downlink control channel including a second TPC which commands adjustment of transmission power while transmitting, the specific number of times, the first uplink channel, wherein, while the first uplink channel is being transmitted repeatedly, the first uplink channel can be transmitted according to the transmission power indicated by the first TPC, without reflecting the second TPC.