Metallic materials are used for a broad range of medical implant devises, from vascular stents to hip prostheses. The most commonly employed metal alloy for these applications is 316L stainless steel. Recent research at NIST has shown that dramatic improvements in corrosion resistance and mechanical properties can be realized by substituting powder processed high nitrogen stainless steel (HNSS) for 316L. In order to ascertain the relevance of these new HNSS alloys to the implant community, a series of tests have been devised to compare the biocompatibility of powder processed HNSS to ingot and powder processed 316L. Test results will report on cell viability and inflammatory response among the many tests being conducted in this comparitive study.