Status and perspectives of non-perturbative renormalization in weak decays

We discuss the status and the problems related to the application of the off-shell non-perturbative renormalization method in a fixed gauge to operators relevant to weak decays. In particular, we critically reappraise the method recently proposed for the ΔI = 1/2 rule. We also present a general analysis of the renormalization for the ΔI = 3/2 operators, and apply it to the ΔS = 2 operator.