When the DC voltage (4 V cm(-1)) was applied to the CdSe microcrystals doped indium tin oxide (ITO) thin film prepared by RF-magnetron sputtering method, the red colour luminescence was observed. The luminescence spectrum had two peaks of about 710 and 880 nm, and the ascending tail at longer than 900 nm. It was considered that the luminescence at 710 and 880 nm is electroluminescence, which may be attributable to the surface defect of CdSe microcrystals.