  We address the problem of Gribov copies in lattice QCD. The gluon propagator
is computed, in the Landau gauge, using 302 ($\beta = 5.8$) $12^4$
configurations gauge fixed to different copies. The results of the simulation
shows that: i) the effect of Gribov copies is small (less than 10%); ii) Gribov
copies change essentially the lowest momenta components ($q < 2.6$ GeV); iii)
within the statistical accuracy of our simulation, the effect of Gribov copies
is resolved if statistical errors are multiplied by a factor of two or three.
Moreover, when modelling the gluon propagator, different sets of Gribov copies
produce different sets of parameters not, necessarily, compatible within one
standard deviation. Finally, our data supports a gluon propagator which, for
large momenta, behaves like a massive gluon propagator with a mass of 1.1 GeV.
