  We investigate the possibility of incorporating a chiral fourth generation
into a GUT model. We find that in order to do so, precision fits to electroweak
observables demand the introduction of light (< M_Z) supersymmetric particles.
This also enables us to provide decay channels to the fourth-generation quarks.
Perturbative consistency sets an upper bound on the coloured supersymmetric
spectrum. The upper limit on the lightest Higgs boson is calculated and found
to be above the present experimental lower limit.
