  The low-lying eigenvalue spectrum of the QCD Dirac operator in the
epsilon-regime is expected to match with that of chiral Random Matrix Theory
(ChRMT). We study this correspondence for the case including sea quarks by
performing two-flavor QCD simulations on the lattice. Using the overlap fermion
formulation, which preserves exact chiral symmetry at finite lattice spacings,
we push the sea quark mass down to \sim 3 MeV on a 16^3\times 32 lattice at a
lattice spacing a \simeq 0.11 fm. We compare the low-lying eigenvalue
distributions and find a good agreement with the analytical predictions of
ChRMT. By matching the lowest-lying eigenvalue we extract the chiral
condensate, \Sigma(2 GeV)[MSbar] = [251(7)(11) MeV]^3, where errors represent
statistical and higher order effects in the epsilon expansion. We also
calculate the eigenvalue distributions on the lattices with heavier sea quarks
at two lattice spacings. Although the epsilon expansion is not applied for
those sea quarks, we find a reasonable agreement of the Dirac operator spectrum
with ChRMT. The value of Sigma, after extrapolating to the chiral limit, is
consistent with the estimate in the epsilon-regime.
