The Tevatron and LEP2 experiments presently provide the most
precise direct determination of the mass and width of the W boson.  The
combined results are: M_W = 80.394 +/- 0.042 GeV and Gamma(W) = 2.095 +/-
0.106 GeV.  The results are in excellent agreement with the predictions of the
Standard Model.  In this article the latest results are described and the
systematic errors which could limit further significant improvements in the
precision of these measurements are reviewed.