Eight new cases of chronic filariasis have been discovered in South Jakarta, a non-endemic area. To cut the chain of transmission, administration of diethylcarbamazine (DEC) and albendazole yearly for five years should be performed. Therefore, primary health care workers in South Jakarta require health education to perform filariasis prevention correctly. This research aimed to study the effectiveness of health education on filariasis mass drug administration (MDA) among primary health care workers in South Jakarta. This study used experimental design with pre-post study method. Data collection was done in South Jakarta on the 26 of June 2013 by asking all the attending primary health care workers to fill the questionnaires comprised of eight questions regarding filariasis MDA. The results show that before health education, 83.3% of participants had poor knowledge, 14.8% had average knowledge and 1.9% of participants had good knowledge on filariasis MDA. Following health education, 64.8% of participants had good knowledge on filariasis, 27.8% had average knowledge and only 7.4% of participants had poor knowledge (marginal homogeneity test <0.001). It was concluded that health education is effective in increasing the knowledge of primary health care workers on filariasis MDA.