Drell-Yan lepton pairs produced in the process p (p) over bar ->
l(+)l(-) + X through an intermediate gamma*/Z boson have an asymmetry
in their angular distribution related to the spontaneous symmetry
breaking of the electroweak force and the associated mixing of its
neutral gauge bosons. The CDF and D0 experiments have measured the
effective-leptonic electroweak mixing parameter sin(2) theta(lept)(eff)
using electron and muon pairs selected from the full Tevatron
proton-antiproton data sets collected in 2001-2011, corresponding to
9-10 fb(-1) of integrated luminosity. The combination of these
measurements yields the most precise result from hadron colliders,
sin(2)theta(lept)(eff) = 0.23148 +/- 0.00033. This result is consistent
with, and approaches in precision, the best measurements from
electron-positron colliders. The standard model inference of the
on-shell electroweak mixing parameter sin(2) theta(W), or equivalently
the W-boson mass M-W, using the ZFITTER software package yields sin(2)
theta(W) = 0.22324 +/- 0.00033 or equivalently, M-W = 80.367 +/- 0.017
GeV/c(2)