  We prove in the cases of spherical, plane and hyperbolic symmetry a local in
time existence theorem and continuation criteria for cosmological solutions of
the Einstein-Vlasov-scalar field system, with the sources generated by a
distribution function and a scalar field, subject to the Vlasov and wave
equations respectively. This system describes the evolution of self-gravitating
collisionless matter and scalar waves within the context of general relativity.
In the case where the only source is a scalar field it is shown that a global
existence result can be deduced from the general theorem.
