In this chapter, the results of studies on the application of nanostructured steel sheets to automotive body structures are introduced. A new route to fabricating nanostructured/ultrafine ferritic microstructures without severe plastic deformation is presented. The preparation and evaluation of two kinds of steel sheets, ultrafi ne-grained (UFG) ferrite-cementite (FC) steel and UFG multi-phase (MP) steel are also presented and discussed. The UFG-FC steel showed large strain rate sensitivity in flow stress, while the UFG-MP steel showed a good combination of high strength and large work hardening rate, which improved the dynamic collapse properties of hat columns. It is shown that UFG steels would help further weight reduction of automotive body structures. © 2012 Woodhead Publishing Limited.