  The production of W bosons decaying into a tau lepton and a neutrino with the
tau lepton decaying hadronically has been observed in LHC pp collisions at
sqrt(s) = 7 TeV with the CMS detector. The selection criteria provide a
statistically significant signal on the top of QCD multi-jet and electroweak
backgrounds. A data-driven method for the estimation of the QCD multi-jet
background has been employed.
