Abstract
We present full O(p^{6}) and two-loop calculations on the axial-vector form factors F_A of semileptonic radiative kaon and pion decays in chiral perturbation theory. The relevant dimension-6 terms of the lagrangian are evaluated by the resonance contribution and the results of the irreducible 2-loop graphs of the sunset topology are given in detail. We also explicitly show that the divergent parts in F_A are cancelled exactly as required.