The present status of impregnated mosquito nets and other impregnated materials is discussed. Research projects which have produced most of the publications on this subject were conducted in areas in Africa with relatively high endemicity of malaria. In these areas, usage of impregnated mosquito nets caused substantial reductions in the sporozoite inoculation rates and some reduction in incidence of malaria attacks. However, there was little or no reduction in parasite rates in the human population. In several countries in Asia and the Pacific, vector control with impregnated mosquito nets has been introduced on a large scale, thus proving its affordability and compatibility with local customs in these countries. Substantial reductions in malaria parasite rates have been obtained in areas with low levels of malaria transmission. In order to develop the vector control method which is most appropriate for each area, much more research is needed on the technical and organizational aspects of vector control with impregnated mosquito nets. Examples are given of data already available as well as an indication of gaps in knowledge which still exist and will need more attention. [References: 36]