Austempered ductile iron (ADI) has complex microstructure containing a multiphase matrix called "austferite". The corrosion resistance of ADI is related to its microstructure which is determined by heat treatment parameters (austempering temperature, austempering time, austenitizing temperature and austenitizingtime). In this work, the electrochemical behavior and corrosion resistance of ADI have been investigated by electrochemical and non-electrochemical tests in chloride media. Particular attention has been paid to the influence of austenitization time (30,60,120,180,360 and 390) on the microstructure and their influence on ADI corrosion behavior. It has been shown that ADI austenitization at 850⁰C for different times and austempered at 3600C for three hours has generally ausferritic microstructure. Retained austenite ranges between 20% to 40%. Hardness increasesd with increasing austenitization time. Electrochemical and non-electrochemical testing in chloride solution showed general corrosion and pitting corrosion was observed in one sample in the electrochemical test.