An organic light emitting diode display including a display including data lines, scan lines, sense lines, and pixels electrically coupled to the data, scan, and sense lines, a compensator for sensing first and second driving currents flowing to the pixels corresponding to first and second test data in a compensation mode, to compare first and second reference currents with the first and second driving currents, respectively, and to update compensation data, a signal controller for compensating input data according to the compensation data to generate image data, and for changing the input data into the first and second test data in the compensation mode; and a data driver for generating a plurality of data signals by using one of the image data, the first and second test data, and to supply the data signals to the data lines.