Measurements by neutron inelastic scattering techniques have provided detailed information about the magnetic excitations of substitutionally disordered antiferromagnets. In the dilute systems, such as MnF2/ZnF2, the excitations broaden and decrease in energy with increasing Zn concentration, while in mixed magnetic systems, such as KMnF3/KCoF3 there are usually two branches of the excitations which correspond to excitations propagating largely on one or other of the magnetic ions. Both of these results are in reasonable accord with the predictions of theories based on the coherent potential approximation and with the results of computer simulations. Recent high resolution experiments on the MnF2/ZnF2 system have shown that there is structure in the line shape of the excitations arising from the different excitation energies of Mn ions surrounded by different numbers of Zn neighbors.