ARolls-Royce has successfully established a capability for the HIPping of austenitic stainless steels in nuclear plant. The focus has now been extended to the HIPping of nickel based alloys, whose good material properties make their use in plant increasingly attractive. A development programme has been undertaken, comparing the mechanical property behaviour of HIPped Alloy 600, 690 and 625 with their wrought counterparts. The results are promising, showing acceptable tensile properties and Charpy impact results for the HIPped test pieces that are comparable to, or better than, the wrought data. Hot isostatic pressing (HIP) offers an attractive alternative manufacturing route that is ideal for the production of a small number of high integrity components. HIPped microstructures have the advantage of being isotropic and equiaxed, with uniformly fine grain sizes; properties not normally found in thick-section forgings.