  We discuss the status of supersymmetric grand unified theories [SUSY GUTs]
with regards to the observation of proton decay. In this talk we focus on SUSY
GUTs in 4 dimensions. We outline the major theoretical uncertainties present in
the calculation of the proton lifetime and then present our best estimate of an
absolute upper bound on the predicted proton lifetime. Towards the end, we
consider some new results in higher dimensional GUTs and the ramifications for
proton decay.
