gamma rays from neutralino annihilation.

We calculate the ux of cosmic gamma rays expected from the annihilation of neutralinos in the Galactic halo. Our calculation of the annihilation cross section to two photons improves the existing calculations by inclusion of exact one-loop diagrams for the amplitudes involving Higgs boson and chargino states as well as those involving fermion and sfermion states. A survey of supersymmetric parameter space shows that numerous models would be observable at the 3 level with an air Cerenkov telescope with an exposure of 10 4 m 2 yr.