Background: A cost-effective method to address reading delays is to use computer-assisted learning, but these techniques are not always effective. Methods: We evaluated a commercially available computer system that uses visual mnemonics, in a randomised controlled trial with 78 English-speaking children (mean age 7 years) who their schools identified as needing reading support. School-based individual tutorials usually took place 2-3 times/week. Only the experimental group received the intervention in the first 10 months; thereafter, both the experimental and control groups received the intervention for 6 months. Results: After 10 months, the experimental group had significantly higher standardised scores than the waiting list control group of decoding, phonological awareness, naming speed, phonological short-term memory and executive loaded working memory. Conclusions: The computer-assisted intervention was effective, and this suggests that this medium can be used for reading interventions with English-speaking children.