According　to　the　GFKT-C/8.3/90　FZG　gear　micropitting　test　procedure,　the　average　value　of　gear　tooth　profile　deviation　is　used　as　the　failure　criterion.　Typically,　gear　tooth　profile　deviation　is　measured　using　a　gear　measuring　machine.　In　order　to　do　that　during　the　FZG　gear　test,　the　gears　tested　have　to　be　disassembled　from,　and　assembled　to　the　test　rig.　This　process　is　tedious,　time-consuming　and　is　likely　to　add　uncertainty　to　the　testing　results.　An　in　situ　gear　tooth　profile　measurement　method　has　been　developed　and　applied　in　FZG　gear　micropitting　tests.　The　tooth　profile　of　the　tested　gear　was　measured　in-situ　in　the　gearbox　before,　during　and　after　each　load　stage　of　the　gear　micropitting　test.　An　algorithm　was　developed　to　fit　the　measured　profile　to　its　theoretical　shape.　Furthermore,　a　tooth　profile　change　evaluation　algorithm　was　developed　for　monitoring　the　evolution　of　the　tooth　profile　during　the　duration　of　the　test.　The　whole　methodology　was　exemplified　with　a　wrought　gear　test　case　run　to　pitting　damage.