In the multispectrum high convertor pressurized water reactor, the core is divided into several regions with a different moderator-to-fuel (M/F) volume ratio specified in each region. This results in a variation of the neutron spectrum in the reactor. As the average M/F ratio is low (tight-lattice configuration), the resulting spectrum in the reactor is hard and a high conversion ratio can thus be achieved. In addition, the difference in the M/F ratio allows for a better negative reactivity void response as compared to a similar monospectrum reactor. Analysis and optimization of such a reactor concept are presented and discussed.