The　vitrification　of　a　liquid　occurs　when　ice　crystal　formation　is　prevented　in　the　cryogenic　environment　through　ultrarapid　cooling.　In　general,　vitrification　entails　a　large　temperature　difference　between　the　liquid　and　its　surrounding　medium.　In　our　droplet　vitrification　experiments,　we　observed　that　such　vitrification　events　are　accompanied　by　a　Leidenfrost　phenomenon,　which　impedes　the　heat　transfer　to　cool　the　liquid,　when　the　liquid　droplet　comes　into　direct　contact　with　liquid　nitrogen.　This　is　distinct　from　the　more　generally　observed　Leidenfrost　phenomenon　that　occurs　when　a　liquid　droplet　is　self-vaporized　on　a　hot　plate.　In　the　case　of　rapid　cooling,　the　phase　transition　from　liquid　to　vitrified　solid　(i.e.,　vitrification)　and　the　levitation　of　droplets　on　liquid　nitrogen　(i.e.,　Leidenfrost　phenomenon)　take　place　simultaneously.　Here,　we　investigate　these　two　simultaneous　physical　events　by　using　a　theoretical　model　containing　three　dimensionless　parameters　(i.e.,　Stefan,　Biot,　and　Fourier　numbers).　We　explain　theoretically　and　observe　experimentally　a　threshold　droplet　radius　during　the　vitrification　of　a　cryoprotectant　droplet　in　the　presence　of　the　Leidenfrost　effect.