Aim/Background: Individuals deprived of full hearing ability suffer from many problems in their social, professional, and personal lives. Prolonged hearing deprivation, particularly in children, results in many consequences including loss of control of one’s voice. Impaired hearing control of the voice leads to dysphonia of different degrees. The aim of this study was to analyse acoustic voice parameters in hearing-impaired, school-aged children (7–12 years) and the influence of treatment type on voice quality. Material and method: The subjects in this study were a group of 83 Polish school children, aged 7–12 years. ENT and phoniatric examination were performed on each subject prior to inclusion. Acoustic voice analysis was performed for each individual. The linguistic material was a prolonged [a] vowel. The acoustic analysis was performed with a digital spectrograph KAY 4300B for multidimensional voice analysis MDVP (Multi-Dimensional Voice Profile). The criterion to include patients in the study group was a profound prelingual, sensorineural hypoacusis. Within the study group, four subgroups were categorised according to the use of hearing devices: 20 children without any type of hearing device (HL), 20 children with hearing aids (HA), and 20 children with cochlear implants (CI). The children using hearing aids and cochlear implants were included in the study 6 months after the hearing rehabilitation was implemented. The control group (NH) consisted of 23 normal-hearing children, in the same age group, without any co-existing voice disorders. The statistical level of significance p < 0.05 was used. Results: The selected, clinically significant voice parameters were analysed for the groups of children in the study.