  We show a strong indication of the existence of a large Fermi surface in the
one-dimensional Kondo lattice model. The characteristic wave vector of the
model is found to be $k_F=(1+\rho )\pi /2$, $\rho $ being the density of the
conduction electrons. This result is at first obtained for a variant of the
model that includes an antiferromagnetic Heisenberg interaction $J_H$ between
the local moments. It is then directly observed in the conventional Kondo
lattice $(J_H=0)$, in the narrow range of Kondo couplings where the long
distance properties of the model are numerically accessible.
