We present the first observation of the all hadronic decay of
tt-bar pairs. The analysis is performed using 109 pb-1 of p anti-p collisions
at s**(1/2) = 1.8 TeV collected with the Collider Detector at Fermilab. We
observe an excess of events with five or more jets, including one or two b
jets, relative to background expectations. Based on this excess we evaluate
the production cross section to be in agreement with previous results. We
measure the top mass to be 186 +/- 10 +/- 12 GeV/c2.