We have investigated the strain relaxation behavior of InGaN/GaN multiple quantum wells (MQWs) with high indium composition using transmission electron microscopy (TEM). We found that the position of the main emission peak in the MQWs with indium content of more than the critical composition is significantly affected by the increase in the number of quantum wells (QWs). From high-resolution TEM (HRTEM) and energy dispersive X-ray spectroscopy (EDX), the redshift by the increase of QW numbers originates from the increase of indium segregation in the MQWs, and dislocations and stacking faults may enhance the formation of the indium segregation. (C) 2003 Elsevier B.V. All rights reserved.