The FIM atom probe has been used to study the atomic scale distribution of chemical elements in several important ferrous materials. Microanalysis of patented and drawn pearlitic steel wires reveals the partitioning of alloying elements between the carbide and ferrite phases. Studies of a similar material in the martensitic state show the progressive redistribution of carbon atoms during the martensite ageing process. Accurate phase analysis of a duplex stainless steel confirms and extends previous X-ray microanalytical studies, and reveals details of alloy element partititoning between austenite and ferrite.