Recently, valuable combinations of mechanical properties with strength of 1.9 GPa accompanied by very decent ductility of 19 and toughness of 31 J, have been achieved in a set of nanostructured bainitic steels. However, it is necessary to elucidate the significance of various microstructural features responsible of that extraordinary mechanical response in more detail. Thus, using two steels, with different Mn, Ni and V contents, and changing the nanostructured bainite isothermal transformation temperatures (200–300°C), has led to a plethora of subtle and essential microstructural variations, necessary to explain how the mechanical response of nanostructured bainite is attained.