A trial was carried out to evaluate the efficiency of releasing namely egg parasitoid, Trichogrammatoidea backs. Nagaraja to control the cotton bollworms; pink bollworm (PBW) and spiny bollworm (SBW), compared to insecticides, in cotton fields at Sakha Research Station, Kafr EI-Sheikh Govemorate for three successive cotton growing seasons 1999-2001. Highest rates of infestation in fallen cotton flower buds and/or squares reached 56, 56 and 62 % with CLW, SSW and PBW, re­spectively. Highest rates of infestation (44 and 40 %) were recorded in the green bolls infested with 513W and PBW, respectively. Parasitoid re­leases proved best results in reducing PBW infestations in the fallen cot­ton flower buds and/or squares and the green bolls compared with both insecticide and check treatments. The reduction attained 9.4, 39.4 and 7.7 % in the fallen cotton flower buds and/or squares, and 36.5, 41.7 and 25.4 % in the green bolls in seasons 1999, 2000 and 2001, respec­tively. In case of the SBW, the results varied from one treatment to an­other and from one season to another. Superior reduction figures of SBW infestation were achieved when the IGR (Ateroon) + parasitoid were al­ternatively applied compared with both the parasitoid releases and/or in­secticide applications. The reduction reached 4.6, 27.9 and 63/ % in the green bolls In seasons 1999, 2000 and 2001, respectively. Highest numbers of predators was recorded in Trichogramma released areas (47 %), followed by the control (34.8 %), the insecticidal treated areas were the least (17.6 %).