  In supersymmetric models, the CP asymmetry produced in the decay of the
lightest right-handed neutrino, $\equiv epsilon$, can be written as a function
of weak scale parameters. We introduce a way of separating epsilon into
contributions from the various weak-scale phases, and study the contribution of
potentially measurable neutrino phases to leptogenesis. We find that the
Majorana phase phi', which could have observable effects on neutrinoless double
beta decay, is important for epsilon unless there are cancellations among
phases. If the phase delta can be measured at a neutrino factory, then it
contributes significantly to epsilon over much of parameter space.
