Objective. To analyze a range of chromosomal abnormalities in 5-6-day-old embryos using array comparative genomic hybridization (aCGH) and next-generation sequencing (NGS) methods in two centers for assisted reproductive technologies (ART) and to compare the results after applying two methods. Materials and methods. Trophectoderm samples of 1041 embryos were studied. NSG was performed on the platform Illumina MiSeq with VeriSeq PGS Library Prep Kit (Illumina); aCGH was conducted using microarray kit G5963A, Agilent. Results. Single chromosome aneuploidy rate starts increasing after 30 years of age, and aneuploidy involving two or more chromosomes after 37 years. In our sampling aCGH and NGS methods showed a similar effectiveness for performing PGT-A. Statistically significant differences in the incidence of chromosomal abnormalities between two ART centers were not revealed. Conclusion. The decrease in the proportion of embryos with balanced chromosome complement is the most impor-tant factor which reduces reproductive potential of women of advanced reproductive age undergoing IVF. Both methods aCGH and NGS demonstrate a similar effectiveness for performing PGT-A. The incidence of chromosomal abnormalities of various types did not differ in embryos cultivated in two IVF centers which took part in the investigation.