EPR linewidth measurements at 24.43 GHz have been made near the critical pointTNof MnF2. Comparison with similar measurements at 9 and 35 GHz shows that the EPR linewidth nearTNdepends on the Larmor frequency, its magnitude at a given temperature being smaller at higher frequencies. This is the first observation of this effect recently predicted by Kawasaki. It is suggested that the observed frequency dependence nearTNis due to breakdown of the usual exchange narrowing condition.