An organic light-emitting display includes: a display panel, scan and data drivers, an ADC, a controller, and a data switch. In a first initialization period, the data switch connects data lines to the data driver, which applies an initialization voltage thereto. In a first sensing period, the data switch connects the data lines to the ADC. The ADC receives analog sensing signals corresponding to first voltages of the data lines, and converts the analog sensing signals into digital sensing signals output to the controller. In a second initialization period, the data switch connects the data lines to the data driver, which applies the initialization voltage thereto. In a second sensing period, voltages at the data lines change to second voltages, the data switch connects the ADC to the data lines, and the ADC converts analog sensing signals corresponding to the second voltages into digital sensing signals output to the controller.