Alkaline phosphatase activity was determined in the digestive system of the desert locust, Schistocerca gregaria (Forskal), using ^-nitrophenylphosphate disodium as the substrate. The enzyme has an optimum pH of 7.4 and a linear relationship between its concentration and activity. The Michaelis constant was found to be 1.4 x 10~4M. The enzyme showed a zero order of kinetics, with an incubation period of up to 25 minutes at an optimum temperature of 40°C. The temperature coefficient (Qio) was 1.960 between 5-15°C and 10-20°C, 1.900 between 20-30°C and 25-35°C, and 1.850 between 30 and 40°C. Salt solutions of MnCl2, MgCl2, CuCl2, and CoCl2 activated the enzyme, while Na2HAsO4, Na2HPO4, CuSO4, FeCl2, and CdCl2 inhibited the activity. Maximum activation was produced by 0.01 M MnCl2.