We present a preliminary measurement of the mass of the W vector
boson using the decays $W\rightarrow e\nu$ and $W\rightarrow\mu\nu$.
The mass of the W is an important parameter of the standard model.
Through its relation to both the top quark and the higgs sector, it
provides a sensitive probe of the electroweak theory.
During the last run of Fermilab's Tevatron, CDF
recorded $\overline{p}p$ collisions at $\sqrt{s}$~=~1.8~TeV corresponding to
an integrated luminosity of 19.3~pb$^{-1}$.
An analysis of both decay channels yields a combined mass measurement of
M$_W$~=~80.38 $\pm$~0.23~GeV/c$^2$.