The mass of the top quark M_top is interesting both as a
fundamental parameter of the standard model and as an important input to
precision electroweak tests.  The Collider Detector at Fermilab (CDF) has a
robust program of top quark mass analyses, including the most precise single
measurement, M_top = 173.4 +/- 2.8 GeV/c2, using 680 pb-1 of p anti-p
collision data.  A combination of current results from CDF gives M_top =
172.0 +/- 2.7 GeV/c2, surpassing the stated goal of 3 GeV/c2 precision
using 2 fb-1 of data.  Finally, a combination with current D0 results gives
a world average top quark mass of 172.5 +/- 2.3 GeV/c2.