Vitrification, of both gametes and embryos, has allowed making “in vitro” fertilization treatments more flexible, safer and effective for our patients. That is why it is an essential part of everyday workflow in assisted reproduction laboratories. Although the replacement of the slow freezing protocols by vitrification made a big change in both survival of the different stages and thus in clinical results, there have been few changes in terms of the vitrification/devitrification protocols.

A well understanding of the theoretical basis of the process as well as the points at which it is carried out, can make the results continue to improve.

Therefore, the aim of this course is to go in deep in the theoretical basis of freezing/vitrification of biological samples, emphasizing the critical points of the process that can influence the results and that can be overlooked in the routine of work (laboratory temperature, surfaces, types of media, volumes,...). Secondly, we will talk about vitrification and the possibility of reducing exposure to cryoprotectants, saving in the laboratory both time and toxicity on the cells. Moreover, the shortening of the devitrification process, eliminating two steps in the process and the presentation of the clinical results obtained to date. Finally, sperm freezing is key for the complete improvement on vitrification processes in the IVF laboratory.