  This paper describes a measurement of the W boson transverse momentum
distribution using ATLAS pp collision data from the 2010 run of the LHC at
sqrt(s) = 7 TeV, corresponding to an integrated luminosity of about 31 pb^-1.
Events from both W -> e nu and W -> mu nu are used, and the transverse momentum
of the W candidates is measured through the energy deposition in the
calorimeter from the recoil of the W. The resulting distributions are unfolded
to obtain the normalized differential cross sections as a function of the W
boson transverse momentum. We present results for pTW < 300 GeV in the electron
and muon channels as well as for their combination, and compare the combined
results to the predictions of perturbative QCD and a selection of event
generators.
