A recent rise in home computer ownership has seen a growing number of children using computers and accessing the internet from a younger age. This paper examines the link between children's home computing and their academic performance in the areas of reading and mathematics. Data from the nine-year-old cohort of the Growing Up in Ireland survey is adopted for this study. The survey reveals that searching for information is a more popular activity among the children than communicating online. Through regression analysis we find that using a computer is positively and significantly associated with children's reading and mathematics scores in standardised tests. This result holds after controlling for multiple determinants of school performance. In addition, we investigate the effects of using various applications on the computer. Surfing the internet for fun, doing projects for school and emailing are associated with higher reading and maths test scores, while those who are permitted to use the computer unsupervised tend to have higher maths test scores. Instant messaging and downloading music or watching movies are negatively associated with both reading and maths scores. The results indicate that some forms of early computer use have significant associations with academic performance among children in primary school, although we could not establish the direction of causation definitively. (Contains 6 tables and 2 notes.)