The structure of the surface layers and the corrosion resistance of austenitic stainless steels after silicon-ion implantation, were examined. The implanted silicon doses were 1.5 x 10(17), 3 x 10(17) and 4.5 x 10(17) Si+ cm(-2). Implantation with all these doses gave an amorphous surface layer. When samples implanted with 1.5 x 1017 Si+ cm(-2) were annealed at temperatures of 300 and 500 degrees C, their surface structure remained unchanged. After annealing at 650 degrees C, the amorphous layer vanished. It was determined how, in terms of corrosion resistance, the amount of implanted silicon, subsequent heat treatment and long time exposure, affect highly corrosion-resistant austenitic stainless steel ( 18/17/8) in comparison to the 316L austenitic stainless steel subjected to the same treatment. Corrosion examinations were carried out in 0.9% NaCl at a temperature of 37 degrees C. After silicon-ion implantation the corrosion resistance of the 316L steel increased while that of highly resistant (18/17/8) did not. The corrosion resistance of the investigated steels, both implanted and non-implanted, increased with the exposure time of the samples in the test environment.