OBJECTIVE The main purpose of the present study was to compare the consonant error patterns of Dutch prelingually deaf CI children with prelingually hearing-impaired hearing aid (HA) children. The authors hypothesized that subjects using conventional hearing aids would have poorer consonant production skills. Additionally, the impact of the age at implantation (CI) and the degree of hearing loss (HA) was determined. METHODS This is a comparative study of 29 prelingually deaf CI children (m.a. 9;0 y) and 32 prelingually hearing-impaired HA children (m.a. 9;11 y) who received their first hearing aid before the age of 2 years. Nineteen CI children were implanted before the age of 5 years. Nine HA children had thresholds above 90dB (range: 91-105dB), 15 between 70 and 90dB (range: 72-90dB) and 8 below 70dB (range: 58-68dB). Speech samples of all the children were elicited by means of a picture naming test and were video-recorded for further phonetic and phonological analysis. RESULTS Considerably more phonetic and phonologic errors were observed in the HA children with thresholds above 70dB (range: 72-105dB). No notable differences could be found between deaf CI children and HA children with thresholds below 70dB. Even children implanted after the age of 5 years showed significantly fewer phonetic and phonological errors than HA children. CONCLUSIONS The consonant production of implanted children is more adequate than the consonant production of HA children with a hearing loss of 70dB or more. In addition, the results also indicate that even after the age of 5 years, implantation can still have an advantageous effect on a child's consonant production.