  The neutrino role in primordial nucleosynthesis is reviewed. The importance
of nonequilibrium effects is emphasized both for the standard massless and
possibly massive neutrinos. The upper bound on tau neutrino mass is presented.
A spatial variation of primordial abundances and a possibility of observing
them by precise measurements of the CMB anisotropy are considered.The
nucleosynthesis bounds on the parameters of neutrino oscillations into sterile
neutrinos are discussed.
