Catolaccus grandis, an ectoparasitoid of the boll weevil was reared in laboratory conditions on the cowpea weevil (Callosobruchus maculatus), as an alternative host for cost reduction in a mass propagation system. Total fecundity, daily oviposition, net reproductive rate, and sex ratio were evaluated and compared to females reared on boll weevils. The data showed that to a certain degree, the cowpea weevil was a viable alternative host for the rearing of C. grandis. It was seen, that after 10 generations of continuous rearing, C. grandis females showed a significant switch in host acceptance as an oviposition site; reason for which, it is not recommendable the rearing of C. grandis on cowpea weevils for more than one generation. However, alternating hosts may be an acceptable practice, given that no significant preference effects were recorded on first generation C. grandis females reared on the cowpea weevil.