  We calculate the two-loop QCD anomalous dimension matrix (ADM) gamma^(1)_NDR
in the NDR-MSbar scheme for all the flavour-changing four-quark dimension-six
operators that are relevant in both the Standard Model and its extensions. Both
current-current and penguin diagrams are included. Some of our NDR-MSbar
results for Delta F=1 operators overlap with the previous calculations, but
several others have never been published before. In the case of Delta F=2
operators, our results are compatible with the ones obtained by Ciuchini et al.
in the Regularization-Independent renormalization scheme, but differ from their
NDR-MSbar results. In order to explain the difference, we calculate the ADM of
Delta F=2 operators again, extracting it from the ADM of Delta F=1 operators.
