In an organic light emitting display device which displays an image in a first mode or a second mode, the organic light emitting display device includes: a first scan driver which supplies a first scan signal having a first voltage to first scan lines; a second scan driver which supplies a second scan signal having a second voltage larger than the first voltage to second scan lines; and a pixel unit including pixels each coupled to a corresponding first scan line and a corresponding second scan line. When a first image displayed in the second mode is changed to a second image to be displayed in the second mode, the second image is displayed in the first mode during a predetermined portion of a period, in which the second image is displayed, and is displayed in the second mode during the remaining portion of the period.