The electronic and optical properties of ZnxCdl-Se-x are investigated using the empirical pseudopotential method (EPM). For the ternary alloy ZnCdSe, the virtual crystal approximation (VCA) is coupled with the pseudopotential method. The energies of F, X and L of ZnxCdl-Se-x alloy versus concentration of Zn are calculated. Pseudocharge density and band structure of Zn0.5Cd0.5Se are also calculated. Other quantities such as refractive index, ionicity character by means of a recent model and transverse effective charge are calculated. (C) 2003 Elsevier Science B.V. All rights reserved.