Abstract: This paper reported on improved in vitro cultute system of human lymphatic filarial larvae. Four culture systems were used. Third-stage larvae of Brugia malayi were best maintained, developing and molted twice in the medium containing modified RPMI-1640 medium, supplemented with 20% newborn calf serum and fauman embrsyonic kidney cell line as feeder layer. This culture system kept larvae alive up to 54 days. Brugia malayl third-stage larvae began to moult on the 8-10th day and again on the 32-36th day; Wuchereria bancrofti third stage larvae grew and developed to the fourth-stage and juvenile and survived to 57 days. They began to moult on the 12-18th days and again on the 32-44th day. This culture system was thought to be useful for studies on morphology and sensitivity to drugs.We also studied several cell-free culture systems. Among them, Best survival, growth and devclopment were obtained in 1:1 mixture of modified RPMI-1640 and TC199 medium supplemented with 20% newborn calf serum. Both Wuchereria bancrofti. and Brugia malayi third-stage larvae grew and developed to the fourth stage larvae and juveniles and survived to 36 days and 42 days respectively. The availability of such culture systems for human filariasis would facilitate studies of biochemistry, immunology, duction of moncclonal antibodies and vaccine.