The corrosion behavior of a number of conventional and high alloy stainless steels has been investigated at 50°C in aqueous solutions containing varying Cl − concentrations (300-5000 ppm) and natural seawater. The stainless steels, austenitic: 304L, 316L, 317L and 904L; martinsitic: 410 and 17-4 pH; superaustenitic: 254SMO, 654SMO, 1925hMo, 3127hMo, 20Cb3 and Remanit 4565; superferritic: Monit 44635 and Remanit 4575 and Duplex:2205 have been included in the studies. Both immersion and salt spray tests were employed to study the corrosion behavior. Transient electrochemical techniques were used to investigate the performance of materials in seawater. The corrosion rates were determined by an electrochemical linear polarization technique. The crevice corrosion resistance of the alloys was studied using both exposure and accelerated techniques. It has been shown that corrosion rate and pitting potential E pit of the steels in seawater are the functions of Cr ± Ni content, pitting resistance equivalent, PRE N and induction time, t i. The superaustenitic and superferritic steels exhibit weight losses less than 50 micrograms during 5000 hours salt spray tests.