Combined effect of Steinernema sp. and entomopathogenic fungus Metarhizium anisopliae was investigated against desert locust, Schistocerca gregaria under laboratory conditions. Interaction of nematode and fungus isolates in vitro revealed that Steinernema sp. isolates SFN.27 and ATs inhibited conidiospores germination of isolates C1 and C2 of M. anisopliae while nematode isolate AT4 did not inhabit the germination of fungal isolate C3. S. gregaria 3^rd instar and adult stage were exposed to different concentrations of M. anisopliae (C3) and Steinernema sp. (AT4). Insects were applied with nematode simultaneously or 1 and 2 days after application of M. anisopliae. The simultaneous and sequential application with both pathogens resulted in additive or a synergistic effect on S. gregaria. These applications increased the mortality of 3^rd instar and adult stage of S. gregaria and reduced time until mortality. The results showed that the simultaneous treatment of both Steinernema sp. and M. anisopliae (C3) at the same host S. gregaria encourage nematode development and inhibit fungal mycoses. However, the sequential exposure treatments encourage fungal mycoses and inhibit nematode development.