Speech and language training for deaf children is carried out at our clinic by the Kanazawa Method, an integrated approach consisting of reception and production training in sign language along with auditory/oral language and written language training. In the present investigation we analyzed the long-term effects of training by the Kanazawa Method on the fundamental frequencies (F0) of a group of 40 hearing-impaired subjects who were enrolled in our program before entering elementary school. Speech samples were collected and acoustic analysis was performed for all the study subjects as well as for a group of normal control subjects. The results obtained were as follows. (i) Hearing-impaired male and female subjects trained by the Kanazawa Method showed long-term improvement in voice quality as manifested by a gradual and steady decline in the absolute and mean values of their fundamental frequencies in parallel with age advancement. (ii) Hearing-impaired subjects of both genders who started training by the Kanazawa Method earlier in infancy showed better long-term improvement in fundamental frequencies compared to those who started training at a later age. These results point at a considerable potential for training by the Kanazawa Method to produce long-term improvement in the voice quality of hearing-impaired children. Our data also suggest that the earlier a hearing-impaired child starts training by the Kanazawa Method, the better his chance for long-term acquisition of a near normal value of fundamental frequency.