The void microstructure produced in a cold-worked Type 316 stainless steel by 5-MeV Ni⁺⁺ ion bombardment has been studied. Within the temperature range 525 to 730°C, the void swelling shows a maximum at ∼620°C. However, void formation extends to a temperature of 800°C. The results are consistent with those from neutron irradiation studies where the temperature shift is considered. The void swelling is dependent on (dose)mwhere m is in the range 2.5 to 3.3. A maximum swelling of 6 percent at 585°C and 125 displacements per atom were calculated. No saturation in the swelling was observed. Precipitates had a marked effect on the void distribution. The results agree reasonably well with results of similar studies using heavy ion bombardment.