This paper looks into the influences of solution treatment on the cavitation erosion and corrosion resistances of a CrMnNi austenitic stainless steel. Cavitation erosion pit formation is mainly associated with twin boundaries, slip lines and martensite traces (epsilon and alpha'). These pits subsequently grow both across slip lines and martensite traces and along twin boundaries, eventually coalescing to form bigger ones. Conducting solution treatment at an excessively high temperature will result in significant grain growth that compromises strength, reduces corrosion resistance and facilitates martensite formation, thereby causing a deterioration in both cavitation erosion and corrosion resistances.