A new methodology to study in-situ the pitting corrosion of stainless steels (at high temperature and high pressure) was developed. This methodology allowed the real-time in-situ anodic polarization while determining the sites for pit initiation in different alloys (SMSS: S13Cr and 15Cr) in chloride containing environments. The methodology allowed measurements at two temperatures 40oC up 180oC with a CO2+H2S pressure of 580 psi (40 bar).