An organic light-emitting display comprises: a display panel with a plurality of pixels; a plurality of source driver ICs comprising sensing blocks that are connected to the pixels and sense the electrical characteristics of the pixels; and a calibration block that applies test currents to the sensing blocks in order to sense offset variations between the sensing blocks in a preset calibration mode. The calibration block comprises: a plurality of discrete current sources that generate the test currents; and a switch array that connects the source driver ICs and the discrete current sources, wherein two or more neighboring source driver ICs share one discrete current source, and each source driver IC is selectively connected to two or more discrete current sources.