Abstract: Experiments were carried out to compare between antigens, extracted from blooc stage of P. cynomolgi, from in vitro culture and infected monkey, using ELISA to detect antibody to vivax-malaria. The results showed a positive rate of 96.9% among 64 cases with vivax-malaria 19-90 days after the onset of attack with both antigens and the titres for the two antigens were quite similar. However, mature parasites can be collected more readily from cultures in vitro and the antigens extracted from them can be prepared freshly. Accordingly, the problem of reactivity loss of antigenicity upon storage can be solved. Once more, the usefulness of PVC film to replace the traditional plates and harmless TMBS as substrate of HRP were confirmed in ELISA for the detection of antibodies to vivax malaria.