We have studied the null-plane hamiltonian structure of the free Yang-Mills fields and the scalar chromodynamics ($SQCD_{4}$). Following the Diracs procedure for constrained systems we have performed a detailed analysis of the constraint structure of
both models and we give the generalized Dirac brackets for the physical variables. In the free Yang-Mills case, using the correspondence principle in the Diracs brackets we obtain the same commutators present in the literature.
