  We analyze neutrino oscillation for the general case when the initial
neutrino is not in a pure flavor state. We show that, after such a neutrino
beam propagates for a while, the probability of detecting any pure flavor state
depends even on the CP-violating Majorana phases in the mixing matrix. The
dependence remains even when energy spectrum of the initial beam is taken into
account. We discuss various implications of this dependence.
