The structural and electronic properties of the dominant intrinsic defect of the Cd vacancy (V-Cd) and the Cl impurity in CdTe are studied using density functional theory. V-Cd is calculated to be a shallow double acceptor. Cl will substitute Te site (Cl-Te) and then act as a shallow donor in CdTe. Moreover, ClTe can bond with V-Cd, forming the defect complexes of Cl-Te-V-Cd. Cl-Te-V-Cd is a shallower acceptor than that of V-Cd. The defect complexes of (Cl-Te-V-Cd)(-1) can improve the p-doping behavior of CdTe. (C) 2013 Elsevier B.V. All rights reserved.