  We study the effect of magnetic field on the dominant neutrino emission
processes in neutron stars.The processes are first calculated for the case when
the magnetic field does not exceed the critical value to confine electrons to
the lowest Landau state.We then consider the more important case of intense
magnetic field to evaluate the direct URCA and the neutronisation processes. In
order to estimate the effect we derive the composition of cold nuclear matter
at high densities and in beta equilibrium, a situation appropriate for neutron
stars. The hadronic interactions are incorporated through the exchange of
scalar and vector mesons in the frame work of relativistic mean field theory.
In addition the effects of anomalous magnetic moments of nucleons are also
considered.
