  We show that discovery of baryon number violation in two processes with at
least one obeying the selection rule \Delta (B-L) = \pm 2 can determine the
Majorana character of neutrinos. Thus observing p \to e^+ \pi^0 and n \to e^-
\pi^0 decays, or p \to e^+ \pi^0 and n-nbar oscillations, or n \to e^- \pi^+
and n-nbar oscillations would establish that neutrinos are Majorana particles.
We discuss this in a model-independent effective operator approach.
