The electronic structure of GaxIn1-xAsyP1-y quaternary alloy, calculated by recursion method is reported. A five orbitals sp(3)s* per atom model was used in the tight-binding representation of the Hamiltonian.

The local density of states and its orbital decomposition (LDOS), integrated density of states (IDOS) and structural energy (STE) were calculated for Ga, In, As and P sites in Ga0.5In0.5As0.5P0.5, GaInAsP lattice matched to InP and lattice matched to GaAs as well. There are 216 atoms arranged in a zinc-blend structure. The calculated quantities are as expected for such systems.