[en] Proton decay due to d=5 operators in SUSY GUT models are considered. Matrix elements of appearing four fermion operators are calculated. Experimental lower bound for proton life time lead to an upper bound for W-bosino Majorana mass: Msub(lambdasub(W)) < 5 GeV. A model with softly broken low energy SUSY and natural suppression of lambdasub(W) and lambdasub(Z) Majorana masses is presented. In this model d=5 operators produce proton decay through Majorana gluino mass. The only decay mode is p → Ksup(+)ßsub(μ). For Mlambdasub(g)=13 GeV are obtained tausub(p)=10₃₁ years