The Filariasis Control Program was established more than 30 years ago in the country and the disease is still a public health problem in some states. Since 1983, a total of 17 filariasis control teams were formed throughout the country to carry out filariasis control work. The teams conduct house and population censuses, nocturnal mass blood surveys and treatment of microscopically confirmed cases. Individual case follow-up is being carried out after 3-5 months while the locality is resurveyed after about 2-3 years. During the years 1988 to 1990, there appeared to be a decreasing trend in the number of filariasis cases detected countrywide. In 1991, brugian filariasis accounted for 92% of the cases detected. The microfilaria rate (MFR) also showed a decreasing trend countrywide for the years 1988 (0.57%) to 1990 (0.35%) but there was an increase in 1991 although it remained well below the 5% MFR targeted in the program objective, In 1991, the filariasis control teams and the district multi-purpose teams collected a total of 167, 151 blood slides out of which 871 were found to be positive for microfilaria. To determine the true endemicity of filariasis in the country, the malaria district multi-purpose teams are also utilized to assist in probe surveys in new areas of the district. Two species of filarial worms, namely Brugia malayi and Wuchereria bancrofti, and the mosquito vectors belonging to the Anopheles and Mansonia genera are involved in the transmission of filariasis in Malaysia. Monkeys and domestic cats are the reservoir hosts for the subperiodic strain of B. malayi.