Working memory, language, and reading comprehension are strongly associated in children with severe and profound hearing impairment treated by cochlear implants (CI). In this study we explore this relationship in sixteen Swedish children with CI. We found that over 60% of the children with CI performed at the level of their hearing peers in a reading comprehension test. Demographic factors were not predictive of reading comprehension, but a complex working memory task was. Reading percentile was significantly correlated to the working memory test, but no other correlations between reading and cognitive/linguistic factors remained significant after age was factored out. Individual results from a comparison of the two best and the two poorest readers corroborate group results, confirming the important role of working memory for reading as measured by comprehension of words and sentences in this group of children.