A total of 2095 patients with fever were tested for malaria and classified according to ABO blood groups. Only 696 cases were malaria positive. While blood group A, B and O were equally susceptible to malaria infection, AB blood group had less number of persons with malaria parasites. A significantly lower frequency of Plasmodium falciparum was observed among individuals with blood groups A and O. In other two blood groups B and AB, no difference in P. vivax and P. falciparum proportions were observed. A two-year study showed that the frequency of repeated attacks between all blood groups was similar.