  We present the first observation in hadronic collisions of the electroweak
production of vector boson pairs (VV, V=W,Z) where one boson decays to a dijet
final state . The data correspond to 3.5 inverse femtobarns of integrated
luminosity of ppbar collisions at sqrt(s)=1.96 TeV collected by the CDFII
detector at the Fermilab Tevatron. We observe 1516+/-239(stat)+/-144(syst)
diboson candidate events and measure a cross section sigma(ppbar->VV+X) of
18.0+/-2.8(stat)+/-2.4(syst)+/-1.1(lumi) pb, in agreement with the expectations
of the standard model.
