This chapter discuses the protocol development and clinical application of aseptic vitrification of human blastocysts. For non-aseptic embryo carrier, the Hemi-straw is used as an embryo carrier device. Vitrisafe is used as an aseptic embryo carrier. The chapter presents the results for the development of an aseptic vitrification protocol. Before an aseptic vitrification is implemented into a routine clinical program, two issues have to be solved to design an embryo carrier device allowing cooling and storage without contact with LN2. The first issue is to be able to achieve and maintain conditions within the embryos that guarantee an amorphous state throughout the cooling as well during the warming process. The second issue concerns the determination of a protocol for exposing blastocysts to cryoprotectants (CPAs) before vitrification in conditions where cooling rates are reduced because of the heat-insulating barrier of the straw in which the blastocysts are kept.