  We consider the effects of a fourth generation of chiral fermions within the
MSSM. Such a model offers the possibility of having the lightest neutral Higgs
boson significantly heavier than in the three generation MSSM. The model is
highly constrained by precision electroweak data, along with Higgs searches at
the Tevatron. In addition, the requirements of perturbative unitarity and
direct searches for heavy quarks imply that the four generation MSSM is only
consistent for tan beta ~ 1 and highly tuned 4th generation fermion masses.
