The G-3 strain of Anopheles gambiae was compared with 2 other strains of An. gambiae and An. freeborni, An. stephensi, and An. dirus for susceptibility to infection with 7 different geographic strains of Plasmodium vivax. Ratios of infection varied, indicating that certain strains of P. vivax were more infectious to the G-3 strain of An. gambiae than to other anopheline species/strains. Based on the comparative number of oocysts per mosquito, the relationships between the 3 strains of An. gambiae were closer than between the G-3 strain of An. gambiae and the 3 other species of Anopheles. Anopheles gambiae appears to be a very useful host for laboratory studies with P. vivax from different geographic origins.