Sound production of children during the first year after cohlear implantation operation (CI) was investigated. The object was 5 children of 3.5-6 years old. 4 children had prenatal risk in anamnesis; 4 children had severe and profound hearing loss, 1 child was deaf. Lessons of children with special teacher were audio and video taped. 15 ours of records were analysed. Perceptive, phonetic, acoustic spectrographic analysis of children’s speech constructions and vidiorecords analysis were made. Sound production of one child was not revealed. Adults - native speakers recognized meaning of some children’s words. Native speakers revealed in children’s sound production stressed vowels [a], [i] that acoustic characteristics corresponded to five years old healthy normally hearing children’s vowels characteristics. Consonants were various in observed children’s sound repertoire, but correct consonant use in words was not realized. CI children’s speech sound mastering was not corresponded completely to speech developm