The acquisition of case and gender marking on the definite and indefinite article was studied in a sample of 6 normally-hearing children and 9 children with cochlear implants. Longitudinal spontaneous speech data are used. Children were matched by MLU, with 4 MLU levels: 1.8, 2.8, 3.6, 4.8. Age ranges for normally-hearing children were 1;4 to 3;8 and for children with cochlear implants 1;8 to 7;0. Frequencies of correctly marked article forms increased over MLU but less so in the hearing-impaired group. In both groups error rates were high. However, error patterns were different. In normally-hearing children errors of case predominated, in hearing-impaired children errors of gender and omission. Error patterns suggest that in normally-hearing children syntactic categorization interacts with input frequency and low discriminability of article forms. In the hearing-impaired group the article system is less advanced, despite higher frequencies of definite articles in adult speech. The predominance of article omission is discussed in terms of persisting perceptual problems or a working memory deficit. (Contains 1 footnote.)