A method for transmitting data in a wireless communication system is disclosed. The method for transmitting data from the user equipment (UE) of the wireless communication system to the network comprises, upon receiving uplink scheduling information from the network, periodically transmitting uplink data to the network according to a first period, and if a buffer status of the user equipment (UE) satisfies a predetermined condition, transmitting buffer status information to the network. The method further includes periodically transmitting uplink data to the network according to a second period different from the first period.