We model the cost-effectiveness of the introduction of a pre-erythrocytic malaria vaccine into the Expanded Program on Immunization. We use a dynamic stochastic simulation model of the epidemiology of Plasmodium falciparum in malaria-endemic areas and of case management in Tanzania. We consider a range of vaccine characteristics and a range of transmission settings. At low vaccine prices, the cost-effectiveness of such vaccines may be similar to that of other established preventative and curative interventions against malaria. The cost-effectiveness ratio increases rapidly and approximately linearly with vaccine cost per dose. The approach can be adopted for comparative analyses of the cost effectiveness of different vaccines and other intervention strategies.