The electronic and optical properties of Zn x Cd 1 - x Se 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 Γ, X and L of Zn x Cd 1 - x Se alloy versus concentration of Zn are calculated. Pseudocharge density and band structure of Zn 0 . 5 Cd 0 . 5 Se are also calculated. Other quantities such as refractive index, ionicity character by means of a recent model and transverse effective charge are calculated.