The invention is an illumination system that incorporates a light emitting diode and a side-emitting light-recycling lens. The side-emitting light-recycling lens recycles part of the light internally generated by a light emitting diode back to the light emitting diode as externally incident light. The light emitting diode reflects a portion of the recycled light, thereby increasing the effective brightness of the light emitting diode. The light reflected by the light emitting diode is directed though the side-emitting light-recycling lens and exits the illumination system, thereby increasing the output brightness and efficiency of the illumination system. The light emitting diode reflects externally incident light with a reflectivity greater than 40 percent.