The cosmological information on neutrino mixing

Cosmology provides interesting information on neutrino mixing models with sterile neutrinos. In this case non standard BBN effects can be relevant. We show how the recent measurement of the baryon content from the observations of CMB anisotropies together with the primordial nuclear abundances measurements can be used to constrain them. In particular four neutrino mixing models are potentially at variance with the cosmological observations. We also discuss the possible scenarios from future experiments.