  Both neutrinoless double beta decay and leptogenesis require neutrinos to be
Majorana fermions. A relation between these two phenomena can be derived once
the mechanism of neutrino mass generation is specified. We first derive the
constraints on the Majorana phases by minimising the effective neutrino mass in
neutrinoless double beta decay with respect to the smallest mass among the
light neutrinos. Given these phases, we derive a lower bound on $M_{1}$ (the
mass of the lightest of the heavy neutrinos) in the framework of Type-I seesaw
mechanism, subject to the constraint that the CP asymmetry required for
adequate leptogenesis is larger than $10^{-8}$. We find that $M_{1} \geq
10^{10}\,(10^{9})$ GeV for the case of Normal (Inverted) hierarchy. We extend
our analysis to the case when one of the heavy neutrinos decouples (two right
handed neutrino models). In this case we find $M_{1} \geq 10^{10}\,(10^{11})$
GeV for the case of Normal (Inverted) hierarchy.
