Voids have recently been reported in stainless steel after irradiation to a high fast fluence (> 1022 n/cm2) at elevated temperatures. The presence of these voids was attributed to the high vacancy concentration resulting from the irradiation. In this paper we wish to report the formation of voids in high purity nickel after a relatively low exposure to neutrons.Nickel foil, 99-997% pure, in the form of disks 14 mm in diameter and 75μ thick was annealed at 700°C for one hour prior to irradiation. Irradiations were performed under two conditions: 1) in a NaK filled capsule equipped with thermocouples and a heater at a temperature of 400°C and 2) in a helium filled capsule at a calculated temperature of 400-450°C. Total neutron fluences were determined from flux wires and were 5 x 1019 n/cm2 and 4 x 1019n/cm2 (E > 1 MeV), respectively.