In the field of dyslexia, cognitive neuropsychological models provide a useful framework for detailed analyses of an individual's reading performance. However, the application of this work to remediation, especially in children, remains relatively unexplored. This study evaluates a lexical treatment programme that has been used successfully in cases of adult acquired surface dyslexia (e.g., Coltheart & Byng, 1989; Weekes & Coltheart, 1986) in the context of severe mixed developmental dyslexia. The results indicate a significant treatment effect that is stable over time and that generalises to untreated words, to spelling, and to some aspects of sublexical processing. Questions related to the use of adult models and methods for developmental conditions and the usefulness of such models in cases of severe mixed dyslexia are discussed. Issues related to treatment generalisation are also explored, with consideration of generalisation of lexical training to sublexical processes, improvement in reading of untreated words, and the effect of reading interventions on spelling performance.