Photo-induced current transient spectroscopy is an efficient technique for the detection and identification of traps in semiconductors. This technique has been used to determine the traps in various semiconductors. CdTe is one of the leading candidates for the development of thin film solar cells; hence, the detection of trap levels in CdTe is of interest for the photovoltaic researchers. In this review special emphasis is given to the photo-induced current transient spectroscopy (PICTS) technique applied in the case of CdTe. The PICTS technique, theory as well as a collection of the majority of the traps in CdTe reported in the literature are presented. (C) 2002 Elsevier Science B.V. All rights reserved.