An organic light emitting display device may include a display panel, a power supply, and a display driver. The display panel may comprise a plurality of scan lines, a plurality of data lines, and a plurality of pixels connected to the scan lines and to the data lines. The power supply may supply a first pixel voltage and a second pixel voltage to the pixels. The display driver may control the display panel. The display panel may display a first image in a first frame frequency during a first driving mode, and display a second image in a second frame frequency that is lower than the first frame frequency during a second driving mode, according to a control by the display driver.