Egg parasitoid Tetrastichus hagenowii is able to parasitize 10 species of cockroach.The experiments were done to find the methods of mass rearing the parasitoid by using american cockroach egg Periplaneta americana as a host for biological control of cockroach. Each one day old parasitoid could parazitise at most, 2 ootheca per day and produce offsprings of 8 male and 46 females per ootheca. The older ones are less efficient. The age of parasitoid are 5 days. Sex ratio female : male are 1:0-1:5, the 1:3 gave the most offsprings, 13 males and 73 females. The other sex ratio gave lesser offsprings, especially 1:0 all the offsprings were male and the least in number. Rearing a lot of parasitoid from one ootheca which has 6 males and 63 females, could produce parasitoid offsprings of 344 males and 2,600 females from 46 oothecas. Oothecas of american cockroach at the age of one day was more able to be parasitized than the older ones upto 15 days. Each female cockroach lays 4, 2 and 1 ootheca per month, and the egg stage are 33 , 37 and 51 days in the hot, wet and cool seasons respectively. The average number of offsprings are 13 per ootheca.