Pieris rapae L. is one of the most economically important pests of Brassicaceae causing extensive defoliation of plants. Entomopathogenic fungi and nematodes are promising biological control agents. The virulence of each of them tested alone against 4^th instar larvae and pupa of P. rapae. The entomopathogenic fungi, Beauveria bassiana showed efficiency against 4^th instar larvae and pupae with LC₅₀: 28.857x10³ and 175.406x10³ spore/ml, respectively. Also, the entomopathogenic nematode, Steinernema carpocapsae was revealed efficacy against 4^th instar larvae and pupae with LC₅₀: 18.148 and 38.96 IJs/larva and pupa, respectively. In addition, the interaction of S. carpocapsae with Beauveria bassiana against P. rapae larvae was studied. An antagonistic effect was clearly seen when S. carpocapsae nematode was applied immediately after the B. bassiana. However, the synergistic or the additive effect was seen when the application of the EPNs 12h after their treatment with B. bassiana.