In this pilot study, we evaluated the effects of the online computer-based training programme 'Lexilogy-Greek' on the reading and spelling performance of young poor readers and spellers. The training is based on psycholinguistic principles that emphasise the importance of acquiring efficient phonological as well as morphological knowledge in remediating reading and spelling difficulties. Our sample consisted of fifteen 5th and 6th grade primary school children. Reading and spelling were tested at three points, with a no-intervention period and subsequently an intervention period in between these time points. We adopted a single group repeated measurement design, and tested for intervention effects using repeated measures ANOVAs. The results revealed substantial treatment effects on spelling, word reading fluency and text reading fluency.