Vocal matching, the ability to imitate phonetic properties of speech, was examined in spontaneous interactions of sixteen dyads of mothers and their hearingimpaired (HI) infants with cochlear implants and age-matched normal-hearing (NH) infants. Mother-infant dyads came to three sessions at three, six, and 12 months postimplantation. Vocal matching was defined as an instance of perceptual and acoustic similarity of vowels and consonants between adjacent maternal and infant utterances.Vocal matching occurred in 25% to 50% of infant and in 17% to 64% of mother vocalizations across dyads. Both mothers and infants in the HI group produced fewer matches as compared to the NH group. However, the number of matches increased in both groups over the period of three testing sessions. These results suggest that vocal matching is a part of interactions between mothers and their HI infants and that pediatric hearing loss affects both infants' and mothers' imitative abilities.