A method and apparatus for performing a scheduling request for transmitting uplink data in a wireless communication system are provided. Specifically, a terminal receives allocation information for a first SR resource that is semi-statically allocated from a base station. The terminal receives allocation information for a second SR resource dynamically allocated from the base station. The second SR resource is additionally allocated in addition to the first SR resource for a buffer status report (BSR). At this time, the allocation information for the first SR resource comprises: mapping information between the first and second SR resources and buffer size information. The terminal transmits an SR to the base station through the first SR resource or the second SR resource.