We discuss the hypothesis that &ggr;‐ray bursts originate in mergers of double neutron star binaries and black hole‐neutrons star binaries at cosmological distances. Such events are estimated to occur in the Universe (out toz∼1) at a rate comparable to the GRO burst detection rate. The total energy released in a merger is ∼5×1053ergs, of which only a fraction ∼10−3has to be emitted in &ggr;‐rays to be detectable at cosmological distances.