none The relationship between infestation of Liriomyza trifolii (Burgess) and their parasitoids in the field of broad beans in Zagazig region, Egypt was studied. The distribution density of L. trifolii mines corresponded sharply with the level of the same plant. Generally there were no or little mines on the upper level, while the middle and lower one were highly infested and reached its maximum at the late season of plantation. The percentage of parasitoids began with a low value and reached also its maximum by 3rd and 5th collection. Both, Diglyphus sp. (Hym., Eulophidae) and Opius sp. (Hym., Braconidae) were the dominate species and more effective agianst L. trifolii than the other three parasitoids namely Hemiptarsenus sp. (Hym., Eulophidae), Halticoptera sp. (Hym., Pteromalidae) and Achrysocharella sp (Hym., Eulophidae) which appeared generally with neglected percentages. The percentage of the parasitoids occurrence was enough to keep the population size of L. trifolii beyond the economic level.