Effect of thermal oxidation on the behaviour of stainless steel (SS) in an ferrichlorid solution was investigated. Sheet specimens of austenitic AISI 316L with the observed area S = 90 cm 2 were immersed into the solution in the initial state, after heating in air isothermally at 200, 400, 600, 800 and 1000°C respectively or in temperature gradient, and after heating and subsequent cleaning of specimens in an nitric acid/hydrofluoride acid mixture. Spot potential profiles of specimens were taken up using a simple device with graphite counter-electrode i.e. by measuring local potential differences between specimen and graphite. The presence of thermal oxides enhances the non-uniformity of profile, which decreases after the removal of oxides by cleaning in the nitric acid/hydrofluoride acid mixture. However, the initial degree of uniformity is not re-established. Prolonged exposure to ferrichlorid solution provokes pitting corrosion of specimens heated isothermally at 400° C and above it or heated in temperature gradient. On such specimens pits number n p , their depths h p and orifice areas S p .