  We construct a new minimal extension of the Minimal Supersymmetric Standard
Model (MSSM) by promoting the $\mu$-parameter to a singlet superfield. The
resulting renormalizable superpotential is enforced by a $\mathcal{Z}_5$
$R$-symmetry which is imposed on the non-renormalizable operators as well. The
proposed model provides a natural solution to the $\mu$-problem and is free
from phenomenological and cosmological problems.
