ac susceptibility measurements have been performed on the dilute antiferromagnet Mn0.35Zn0.65F2 in the absence of an external uniform field. For a driving field of amplitude Hac∼1.0 Oe applied parallel to the easy [001] direction, a frequency-dependent susceptibility has been observed at low temperatures. When the driving field is applied perpendicular to this direction, a departure from the Curie–Weiss behavior indicates that some spin clusters are spatially oriented at low temperatures. The presence of these randomly oriented magnetic moments may cause the random-exchange Ising model to be inappropriate1 in explaining the zero-field behavior near to the percolation concentration xp. A random-anisotropy model may be useful to explain the magnetic features of MnxZn1−xF2 close to xp.