A pixel and an organic light emitting display device using the same, which can improve display quality, are provided. An organic light emitting display device includes pixels, an emission control line, an initial power supply unit, a scan driver and a data driver. The pixels are at intersection portions of scan lines and data lines. The emission control line is commonly coupled to the pixels. The initial power supply unit is commonly coupled to gate electrodes of one or more transistors included in each of the pixels, and supplies a first voltage during a first period, a second voltage lower than the first voltage during a second period, and a third voltage higher than the first voltage during a third period in one frame period. The scan driver drives the scan lines and the emission control line. The data driver drives the data lines.