  Neutrinoless double beta ($\znbb$) decay violates lepton number; its absence
stringently constrains the parameters of theories beyond the standard model in
which the neutrino has a Majorana mass. R-parity violating weak-scale
supersymmetry is a prominent example of such models. Double beta decay in
supersymmetry with explicit bilinear R-parity breaking is discussed and current
limits on the $\znbb$ decay half life of $^{76}$Ge are used to extract upper
bounds on the R-parity breaking parameters of the first generation. Moreover,
it is shown that the effective Majorana neutrino mass, measured in $\znbb$
decay, is non-zero once the 1-loop corrections are taken into account even for
the case of perfect alignment ($\Lambda_i:=(< {\tilde \nu}_i > \mu - v_1
\epsilon_i) \equiv 0$) among the R-parity violating parameters.
