A field trial evaluation of malathion was carried out in the province of Helmand, southwest Afghanistan, in order to evaluate the effectiveness of this insecticide for control of adult Anopheline mosquitoes. Anopheles culicifacies Giles is one of the main vectors of malaria, with an epidemic potential in the lower Helmand province, that showed a strong resistance to DDT in 1972. One round of house spraying with malathion 50% w. d. p. 2g/m2 was carried out in July 1976, at the peak of activity of An. culicifacies. On the basis of the results obtained, it was concluded that malathion is an effective insecticide against An. culicifacies.