The present work is investigating the SCC suscebtibility of four CrMnN stainless steels and one CrNiMo steel with different degrees of cold working. Constant load tests, slow strain rate tests and electrochemical investigations were performed in saturated boiling 45% MgCl2 solution and in 62% CaCl2 solution. Additionally, transmission electron microscopy investigations were accomplished. Absolute threshold stress remains unaffected with increasing amount of cold deformation. Relative to yield strength there is a sharp decrease of threshold stress. The amount of strength that is gained by cold working is not applicable for SCC resistance. Independent of degree of cold deformation, the fracture mode always is transgranular and ductile. Crack propagation of investigated CrNiMo stainless steel is by far slower than for CrMnN steels. The reason for this is a higher dissolution rate of the more active CrMnN steels. The investigations indicated, that the CrNiMo steel is not SCC susceptible in 62% CaCl2 solution. This result argues for the use of highly aggressive 45% MgCl2 solution, which even attacks this highly alloyed CrNiMo steel. Slip step dissolution is considered to be the dominating step for crack initiation. Obviously two different mechanisms are responsible for crack propagation, which is supposed to be a combination of Hydrogen embrittlement and film induced cleavage.