We present a measurement of the W boson mass using data collected by the D0 experiment at the Fermilab Tevatron during 1994–1995. We identify W bosons by their decays to eν final states. We extract the W mass MW by fitting the transverse mass and transverse electron momentum spectra from a sample of 28 323 −→Weν decay candidates. We use a sample of 3563 dielectron events, mostly due to →Zee decays, to constrain our model of the detector response. From the transverse mass fit we measure MW=80.44±0.10(stat)±0.07(syst) GeV. Combining this with our previously published result from data taken in 1992–1993, we obtain MW=80.43±0.11GeV. Received 23 December 1997DOI:https://doi.org/10.1103/PhysRevD.58.092003©1998 American Physical Society