The precipitation and segregation phenomenon in a type 409L Ti-stabilized 11 wt% Cr ferritic stainless steel has been investigated using a transmission electron microscopy and a laser assisted three-dimensional atom probe. In solution treated and aged specimens, a strong segregation and consequent depletion of Cr was observed as well as segregation of C and Ti atoms along the grain boundary. The reason for the Cr segregation and the way to avoid such segregation is discussed.