ISO 13485 was introduced in 1996, which happens to be the last time a major update to 21 CFR Part 820 (QSR) occurred. Since that time, ISO 13485 has been modified a few times, and the most recent version – ISO 13485 – is very similar to FDA QSR.  The FDA says it is now time to harmonise the two by replacing the QSR with the QMSR. The primary change here is that Subpart A of the new proposed QMSR refers to ISO 13485 as the basis for compliance with the QMSR but with some minor modifications as discussed below.  This means that all companies required to comply with the QMSR will essentially be following ISO 13485 even if not certified by a third party. Where differences exist between ISO 13485, the Food, Drug, and Cosmetic Act (FD&C Act) and QMSR, the QMSR will prevail.