Natural abundance of the endoparasitoids Opius pallipes Wesmeal and Chrysocharis parksi Crawford was studied in four tomato greenhouses at Sakha Agricultural Research Station. The greenhouses were planted with the tomato varieties, Hybrid G512 (Greenhouse 1), Hybrid TY 70/84 (Greenhouse 2), TY 70/70 (Greenhouse 3) and TY 71 (Greenhouse 4). The parasitoids showed high  populations in April and May which kept the populations of the serpentine leafminer Liriomyza trifolii (Burgess) at low densities till the end of the season in all studied greenhouses. O. pallipes recorded two peaks of abundance in all greenhouses, the highest peak recorded  7, 5, 7 and 7 individuals/50 infested leaflets in greenhouses 1, 2, 3 and 4 respectively, while the highest average numbers occurred in April in all greenhouses recording 4.5 ± 2.1, 3.1 ± 1.6, 4.5 ± 2.2 and 4.5 ± 2.1 individuals/50 infested leaflets in greenhouses 1, 2, 3 and 4 respectively. The percentages of parasitismreached 30.4 %, 38.5 % , 31.6 %and30.4%ingreenhouses 1, 2, 3 and 4 respectively. C. parksi  recorded two peaks of abundance in all greenhouses. The highest peak recorded  8, 7, 7 and 6 individuals/ 50infested leaflets in greenhouses 1,2,3 and 4 respectively, while the highest average numbers occurred in April in greenhouses 1and 4 recording  5.3 ± 2.1 and 5.2 ± 2.2 individuals/50infested leaflets respectively and in march in greenhouses 2and 3 recording  4.1 ± 1.4 and 4.0 ± 1.4 individuals/50 infested leaflets respectively, while  percentages of parasitismreached 38.1 %, 36.8 %, 27.7 % and38.1% ingreenhouses 1,2,3 and 4 respectively.