This review summarises the recent progress in development of advanced high brightness and white light emitting diodes (LEDs) that have been reported by several laboratories. Two main orientations in LED fabrication based on inorganic and organic semiconductor materials are described. LEDs offer a number of advantages compared to existing light sources in optoelectronic applications. These include increased lifetime, reduced power consumption, higher brightness and better spectral purity. (C) 2003 Elsevier Science B.V. All rights reserved.