  We investigate the predictions for fermion masses in the minimal realistic
non-supersymmetric SU(5) model with the Standard Model matter content. The
possibility to achieve b-\tau unification is studied taking into account all
relevant effects. In addition, we show how to establish an upper bound on the
ultraviolet cutoff \Lambda of the theory which is compatible with the Yukawa
couplings at the grand unified scale and proton decay. We find \Lambda \simeq
10^{17} GeV, to be considered a conservative upper bound on the cutoff. We also
provide up-to-date values of all the fermions masses at the electroweak scale.
