A stereoscopic image display and a method for driving the same are disclosed. The stereoscopic image display includes a display panel that displays a two-dimensional (2D) image data in a 2D mode and display a three-dimensional (3D) image data in a 3D mode, a backlight unit providing light to the display panel, a backlight controller that reduces a duty ratio of the backlight unit in a 3D mode lower than a duty ratio set in the 2D mode, and increases a forward current supplied to light sources of the backlight unit in the 3D mode greater than a forward current set in the 2D mode, and a light source driver driving the light sources of the backlight unit.