Thioglycolic acid (TGA) capped CdTe quantum dots (QDs) have been synthesized in aqueous media. The effect of diamine on luminescence property of TGA capped CdTe QDs has been investigated and it has been found that the diamine significantly affects the optical properties of CdTe QDs. Luminescence efficiency as well as lifetime of CdTe QDs have seen to be enhanced notably up to certain concentration of the ethylene diamine added and the observation is much more pronounced in case of smaller size QDs. The results indicate that the local surface-trap states of CdTe QDs reduced effectively by the EDA treatment. (C) 2011 Elsevier B.V. All rights reserved.