This paper describes a direct measurement of the W boson total decay width ΓW using the DØ detector at the Fermilab Tevatron Collider. The measurement uses an integrated luminosity of 177.3 pb-1, collected during the 2002-2003 run. The width is determined by normalizing the predicted signal and background transverse mass distributions to 75,285 W → eν candidates in the transverse mass region 50 < MT < 100 GeV and then fitting the predicted shape to the 625 candidates in the tail region 100 < MT < 200 GeV . The W width is determined to be ΓW = 2.011 ± 0.093 ( stat ) ± 0.107 ( syst ) GeV .