Neutrino masses from broken R-parity

We review models where R-parity is broken, either spontaneously or explicitly. In this last case we consider the situation where R-parity is broken via bilinear terms in the superpotential. We show that although at tree level only one neutrino gets mass, at one-loop level all three neutrinos became massive. We study the conditions under which bimaximal mixing can be achieved and show that the masses can be in the correct ranges needed for solving the atmospheric and solar neutrino problems.