The CDF collaboration has analyzed ~200 pb-1 of Tevatron Run II
data taken with the CDF II detector between February 2002 and September
2003 to measure the W boson mass. With a sample of 63964 W --> e
nu decays and 51128 W --> mu nu decays, we measure M_W = 80413 +/-
34(stat) +/- 34(syst) MeV/c2. The total measurement uncertainty of 48
MeV/c2 makes this result the most precise single measurement of the W
boson mass to date.