This study was to examine the relations among working memory, sentence comprehension and recognition performance by children with a cochlear implant. 20 subjects, divided in two groups, participated; 10 normal hearing children and 10 children with a cochlear implant. Children were all between 6 and 8 years old. The duration of implant use for all children with a cochlear implant was between 4 and 6 years. In the working memory task, children recalled words under three different processing load conditions (i.e., no-load, single-load, and dual-load conditions). In the sentence comprehension task, children listened sentences and chose one picture that explained the sentences. In the sentence recognition task, children listened the target sentence and repeated it or wrote it down. Results of the memory task showed that two groups were not significantly different. However, the children with a cochlear implant showed poorer performance in recalling words in the dual-load condition than those in the other conditions. On the sentence comprehension and recognition tasks, children with a cochlear implant group showed poorer performance than normal hearing children group. In all the three tasks, there were individual variabilities in children with a cochlear implant group. Results of the relationship among three tasks indicated that scores of dual-load condition task were significantly correlated to those of sentence comprehension and recognition tasks in children with a cochlear implant group. Conclusively, findings suggested that children with a cochlear implant have a similar working memory capacity to that of normal hearing children due to early intervention of auditory, speech and language. In addition, findings from children with a cochlear implant group also indicated that their processing capability, especially a complex process, may influence their language ability.