We have proposed laser-assisted depletion of isotope from a natural isotopic mixture of Gd to enhance its functional efficiency as a burnable poison. Theoretical investigations on laser-assisted depletion of isotope from natural gadolinium have been carried out for two-color resonant three-color photoionization pathways using density matrix formalism. Calculations have been carried out using a density matrix formalism to optimize conditions for high ionization efficiency without much sacrifice in the isotopic selectivity. Optimum conditions for good isotopic selectivity of without significant sacrifice in the ion yield have been identified. Under appropriate conditions, all the 17 photoionization schemes are found to be useful for the laser-assisted separation of isotopes which can be used for reactor applications. The effect of source, laser, and atom parameters on isotopic selectivity and ionization efficiency has been investigated. Among the photoionization schemes investigated, one of the photoionization scheme has been investigated in detail. Under optimized conditions, this photoionization scheme has resulted in high ionization efficiency () and high isotopic selectivity .