Two-loop corrections to the Higgs boson masses in the MSSM

We present a computation of the O(atas + at^2) two–loop corrections to the MSSM Higgs masses. An appropriate use of the effective potential approach allows us to obtain simple analytical formulae, valid for arbitrary values of mA and of the mass parameters in the stop sector. In a large region of the parameter space the O(at^2) corrections are comparable to the O(atas) ones, increasing the prediction for mh by several GeV.