  Recently we have proposed a renormalizable grand unified theory, based on the
SU(5) gauge symmetry, where the neutrino masses are generated through the type
I and type III seesaw mechanisms. In this letter we study the supersymmetric
version of this theory. As in the non-susy version it is possible to generate
all fermion masses with the minimal number of Higgses, the theory predicts one
massless neutrino and the leptogenesis mechanism can be realized. All
contributions to the decay of the proton and the properties of neutralinos are
discussed. This theory can be considered as the simplest renormalizable
supersymmetric grand unified theory based on the SU(5) gauge symmetry since it
has the minimal number of superfields and free parameters.
