Austenitic stainless steels at cryogenic temperatures show an evolving microstructure. In the undeformed state the microstructure is fully austenitic, yet the material straining leads to strain-induced martensite transformation resulting in a biphasic microstructure. In this work, we study the influence of martensitic transformation on the ductile fracture behavior of AISI 304L and AISI 316LN austenitic stainless steels at cryogenic temperatures.