CubicZnShas been used as a model substance to study the influence of long range order vs short range order on the electronic spectrum. Energy bands, wave functions and scattering phases as well as the sensitivity on potential variations have been studied for crystallineZnS. It is found that there are certain states which effectively are determined by l.r.o., whereas others are mainly due to the atomic potentials. Comparison with CBS calculations shows that the latter are virtually unchanged in the amorphous phase.