The methods employed for the addition of uranium to steels and cast iron in the Physical Metallurgy Division are outlined. It has been found that the segregation of uranium is a major problem in aluminum and / or silicon killed steels and that the cooling rate is important in allowing the segregate to settle to one area, which can subsequently be discarded. The unsegregated areas were found to be extremely low in total oxygen, acid insoluble aluminum (Al20 3) and, in some cases, slightly lower in nitrogen. Uranium recoveries, based on analyses of the unsegregated areas, were quite constant, at about 45 per cent, regardless of the type of uranium master alloy used for the addition. No segregation of carbon, manganese, silicon, sulphur, phosphorous, chromium or copper was observed in these steels. In commercial heats, the recoveries ranged from 7 to 29 per cent for ladle additions to oxygen converted steel. When the steel was fully deoxidized prior to the uranium addition, recoveries ranged from 49 to 66 per cent, regardless of the steelmaking process. In large commercial ingots, the segregation of uranium was confined to the bottom of the ingot. Tests were also carried out to show that normal basic electric steelmaking procedures remove uranium from the molten bath, thus indicating that recirculated scrap will not lead to uranium build-up.