We combine six measurements of the inclusive top-quark pair (tt¯) production cross section (σtt¯) from data collected with the CDF and D0 detectors at the Fermilab Tevatron with proton-antiproton collisions at s=1.96 TeV. The data correspond to integrated luminosities of up to 8.8 fb−1. We obtain a value of σtt¯=7.60±0.41 pb for a top-quark mass of mt=172.5 GeV. The contributions to the uncertainty are 0.20 pb from statistical sources, 0.29 pb from systematic sources, and 0.21 pb from the uncertainty on the integrated luminosity. The result is in good agreement with the standard model expectation of 7.35-0.33+0.28 pb at next-to-next-to-leading order and next-to-next-to leading logarithms in perturbative QCD.