  We present the first measurement of the A_2 and A_3 angular coefficients of
the W boson produced in proton-antiproton collisions. We study W-> e+nu and W->
mu+nu candidate events produced in association with at least one jet at CDF,
during Run Ia and Run Ib of the Tevatron at sqrt(s)=1.8 TeV. The corresponding
integrated luminosity was 110 pb^-1. The jet balances the transverse momentum
of the W and introduces QCD effects in W boson production. The extraction of
the angular coefficients is achieved through the direct measurement of the
azimuthal angle of the charged lepton in the Collins-Soper rest-frame of the W
boson. The angular coefficients are measured as a function of the transverse
momentum of the W boson. The electron, muon, and combined results are in good
agreement with the Standard Model prediction, up to order alpha_s^2 in QCD.
