This chapter discusses current methodology and the advantages and limitations of blastocyst biopsy. The first phase of blastocyst biopsy involves making a hole in the zona pellucida (ZP). The dissection of the ZP may be performed mechanically, by the application of acid Tyrodes solution, or through the use of laser technology. The cryopreservation of biopsied embryos continues to be one of the weak points of preimplantation genetic diagnosis (PGD). The results published by most groups show that embryos with an opening in the ZP are more sensitive to the freezing process, which is reflected in reduced survival and developmental rates among frozen-thawed biopsied embryos. Vitrification as an alternative to classical freezing techniques is adopted as part of numerous in-vitro fertilization (IVF) programs due to its simplicity and, above all, the excellent results obtained not only in oocytes but also in early embryos and blastocysts.