  We evaluate the fermionic two-loop QCD corrections to the heavy-quark pair
production process in the quark-antiquark channel. We obtain analytic results
which are valid for any value of the Mandelstam invariants s and t, and of the
heavy quark mass m. Our findings confirm previous results for the analytic
evaluation in the small-mass limit and numerical results for the exact
amplitude. We furthermore provide the expansion of the two-loop amplitude at
the production threshold s ~ 4m^2.
