  We propose an alternative mechanism for leptogenesis at the electroweak
scale, through the decays of a left-handed sneutrino. This scenario may be
realized in supersymmetric models with non-zero Majorana masses for the
neutrino superfield that lead to mixing and mass splitting between the
left-handed sneutrino and the corresponding antisneutrino. Soft supersymmetry
breaking provides new sources of CP violation in sneutrino-antisneutrino mixing
that can generate a lepton asymmetry in decays of the left-handed sneutrino. We
show how the three Sakharov conditions for generating the observed baryon
asymmetry of the Universe can be fulfilled in this restrictive framework.
