We present a measurement of tt¯ production in pp¯ collisions at s=1.8TeV from 110pb−1 of data collected in the all-jets decay channel with the D0 detector at Fermilab. A neural network analysis yields a cross section of 7.1±2.8(stat)±1.5(syst)pb at a top quark mass (mt) of 172.1GeV/c2. Using previous D0 measurements from dilepton and single lepton channels, the combined D0 result for the tt¯ production cross section is 5.9±1.2(stat)±1.1(syst)pb for mt=172.1GeV/c2.Received 20 January 1999DOI:https://doi.org/10.1103/PhysRevLett.83.1908©1999 American Physical Society