  We study ``soft leptogenesis'', a new mechanism of leptogenesis which does
not require flavour mixing among the right-handed neutrinos. Supersymmetry
soft-breaking terms give a small mass splitting between the CP-even and CP-odd
right-handed sneutrino states of a single generation and provide a CP-violating
phase sufficient to generate a lepton asymmetry. The mechanism is successful if
the lepton-violating soft bilinear coupling is unconventionally (but not
unnaturally) small. The values of the right-handed neutrino masses predicted by
soft leptogenesis can be low enough to evade the cosmological gravitino
problem.
