An interior rearview mirror information display system for a vehicle includes an interior rearview mirror assembly including an electrochromic reflective element. A display device is disposed behind a transflective mirror reflector of the reflective element and includes a display screen backlit by a plurality of light emitting diodes supported by a circuit board disposed rearward of the fourth surface of the rear substrate. The light emitting diodes of the circuit board are disposed to the rear of the display screen to provide backlighting of the display screen when activated. Information displayed by the display device is viewable by a driver of the equipped vehicle. When the plurality of light emitting diodes is activated and the display device is displaying information, light emitted by the plurality of light emitting diodes passes through the display screen and through the transflective mirror reflector for viewing by the driver of the equipped vehicle.