  We present a class of extensions of the MSSM characterized by a fully chiral
field content (no mu-terms) and no baryon or lepton number violating term in
the superpotential due to an extra U'(1) gauge symmetry. The minimal model
consist of the usual matter sector with family dependent U'(1) charges, six
Higgs weak doublets, and three singlets required to give masses to the
Higgsinos and cancel anomalies. We discuss its main features such as the tree
level mass spectrum and the constraints on flavor changing processes.
