  We report a measurement of the D0 meson mass using the decay chain D*(2010)+
-> D0 pi+ with D0 -> K- K- K+ pi+. The data were recorded with the BaBar
detector at center-of-mass energies at and near the Y(4S) resonance, and
correspond to an integrated luminosity of approximately 477 1/fb. We obtain
m(D0) = (1864.841 +- 0.048 +- 0.063) MeV, where the quoted errors are
statistical and systematic, respectively. The uncertainty of this measurement
is half that of the best previous measurement.
