OBJECTIVE: The aim of this work is to summarize the current knowledge about preimplantation genetic screening and diagnostics.DESIGN: A review article.SETTING: Department of Gynecology and Obstetrics, District Hospital Sternberk, IVF Clinic, Olomouc.RESULTS: Preimplantation genetic testing is a complex of genetic and molecular cytogenetic examinations, which can help to detect abnormalities in embryos before transfer into the uterus of the mother. These specialized examinations are based on the latest findings in genetics and assisted reproduction. The preimplantation genetic testing is necessarily associated with a method of in vitro fertilization. It is performed on isolated blastomeres on the third day of embryo cultivation. Nowadays, it is preferred trophectoderm examination of cells from the five-day blastocysts. Generally speaking, after preimplantation genetic testing, we can select only embryos without genetic load to transfer into uterus.CONCLUSION: Preimplantation genetic testing is an important part of treatment of infertility. Complex diagnostics and treatment of infertile couples are increasingly influenced by the development and use of advanced genomic technologies. Further development and application of these modern methods require close cooperation between the field of assisted reproduction and clinical genetics.