Regularization of supersymmetric theories

The regularization of supersymmetric theories is discussed, and recent progress on problems of regularization by dimensional reduction is reviewed. Dimensional reduction can be formulated in a mathematically consistent way, consistency with factorization is established, and a succint method is presented that allows for tests whether supersymmetry is preserved by the regularization. Using this method, it can be shown that dimensional reduction preserves supersymmetry in a large range of practically relevant cases, in particular in the case of two-loop calculations of the MSSM Higgs boson masses.