We have studied the degradation mechanism of GaN base blue light emitting diodes by the current-voltage and light current characteristics driving high currents through the diodes for various times. This was a result of an increased non-radiative recombination in the active region. The aging effects were not observed at the high bias region due to the saturation of non-radiative recombination centres. The mechanism of the increased non-radiative recombination centres may be related with the generation of defects in the active region due to the high current flow through quantum well structure and the increase of light emitting diode chip temperature. (c) 2005 Elsevier B.V. All rights reserved.