  The complete fermionic two-loop contributions to the prediction for the
W-boson mass from muon decay in the electroweak Standard Model are evaluated
exactly, i.e. no expansion in the top-quark and the Higgs-boson mass is made.
The result for the W-boson mass is compared with the previous result of an
expansion up to next-to-leading order in the top-quark mass. The predictions
are found to agree with each other within about 5 MeV. A simple
parameterization of the new result is presented, approximating the full result
better than 0.4 MeV for M_H < 1 TeV.
