Under field conditions, preference of host plant by the parasitoid Diglyphus isaea (Walker) was studied. Three winter crops (broad bean, lentil and chickpea) and three summer ones (cowpea, kidney bean and tomatoes) were studied for their preference to D. isaea which is an ectoparasitoid of the leaf-miner Liriomyza trifolii. (Burgess) Results obtained revealed that, broad bean had the highest average monthly rates of parasitism in three successive seasons recording (31.0±12.2, 41.6±19.3 and 39.3±10.6), followed by lentil (15.2±11.8, 8.1±4.8 and 11.2±4.9) and chickpea (4.1±2.8, 3.5±1.9 and 3.6±2.3) during the growing seasons (2004/05, 2005/06 and 2006/07), respectively. In contrast, cowpea had the highest average monthly rates of parasitism by D.isaea on L.trifolii in three successive seasons recording (33.7±8.1, 31.0±8.3 and 35.1±6.1), followed by kidney bean (29.8±11.8, 29.6±6.7 and 29.5±10.1) and tomatoes (25.0±9.7, 20.2±8.3 and 28.4±4.0) with slight differences of preference among them, respectively.