The influence of temperature on efficacy of Beauveria bassiana and Metarhizium anisopliae against the desert locust, Schistocerca gregaria (Forskal), were investigated in the laboratory. Fifth nymphal instar was inoculated by 1.5 ×10³ spores/nymph by topical application using micropipette under the pronotum, at 50% RH. B.bassiana caused mortality for insects at temperature between 22-31°C, and 25°C was the optimum that caused more rapid death and the LT₅₀ was 5.3 days. In contrast M. anisopliae has wide range of temperature that can caused death until 37°C, but 28-31°C was the optimum temperature and the LT₅₀ was 5 days. At this optimums temperature, four doses (1.5×10², 1.5×10³, 1.5×10⁴, and 1.5×10⁵ spore/nymph)were used against 4^th and 5^th nymphal instars of the desert locust. For 4^th nymphal instar, It' was  obvious that M. anisopliae caused rapid mortality among infected 4^th instar nymph comparing with B. basiana at all the tested doses except incase of dose1.5×10² spore /nymph, where treated nymph with B. bassiana died faster than those treated with M. anisopliae. While for the 5^th nymphal instar, It' was clear that M. anisopliae caused significant rapid mortality comparing with B. bassiana in case of dose1.5×10²spore/nymph. While B. bassiana caused significant rapid mortality than M. anisopliae in case dose1.5×10⁴.