Abstract: This investigation was carried out in two malarious villages of different types In Pucheng County, Fujian during the period of 1976 to 1978. 200-400 blood samples were collected randomly in both villages in October by the end of transmission season in each year. For each sample, immunofluorescent antibody test (IFAT) and blood examination were performed simultaneously. It was found that the malaria incidence was closely related to the positive rate of IFAT (p0.05) but less closely related to the positive parasite rate (p0.05). The results suggested that IFAT is a sensitive index for monitoring the endemicity of malaria during the transmissionseason.