Plasmodium falciparum apical membrane antigen-1(PfAMA-1) is one of the leading malaria vaccine candidates which mainly for blood stage. However, genetic variation and antigenic diversity identified in global PfAMA-1 are major obstacles in the development of an effective vaccine based on this antigen, especially on the domain I(DI) of PfAMA-1. In this study, genetic diversity and the effect of natural selection of DI of PfAMA-1 among Bioko island P. falciparum isolates were analysed.