Magnetic Barkhausen noise measurement (MBN) is a relatively new non-destructive detection technique. Its working principle is based on Barkhausen discontinuities or noise when a ferromagnetic material is subjected to a varying magnetic field. MBN is being used to characterise the stress state of a ferritic stainless steel (AISI 430). Other magnetic parameters such as saturation induction (BMax), remnant induction (BR), coercive field (HC) and maximal relative permeability (PMax) derived from the hysteresis loop have also been used to support the results achieved using MBN. Microstructural changes due to cold working and heat treatments were characterized by the applied magnetic measurements. The MBN technique was proved to be a useful non-destructive and quantitative method for microstuctural investigation of the investigated ferritic stainless steel.