Cochlear implantation is the optimal method for hearing and speech rehabilitation in patients with congenital deafness. Over the last several years, the interest to the problems of etiopathogenetic mechanisms of congenital deafness and the results of hearing and speech rehabilitation of patients, mainly of younger children, has increased in international and Russian scientific literature. The two most common factors, according to the data, are cytomegalovirus infection and genetic disorders, associated with mutation of the GJB2 gene encoding connexin-26 – gap-junction proteins, which is responsible for the connection of hair cells of the organ of Corti and dendrites of neurons of the spiral ganglion. However, in the vast majority of scientific works, devoted to the problems of cochlear implantation, the attention of researchers was focused on the audiological and pedagogical aspects of this program, while data on the surgical stage remain relatively small. In our work, we attempted to analyze the features of the surgical stage of cochlear implantation in patients with the most common etiological factors of congenital deafness: a mutation, associated with the GJB2 gene, and persistent cytomegalovirus infection.