Multimedia computer programmes have been found to facilitate learning in children with Autistic Spectrum Disorders (ASD). However, the effectiveness of these resources is limited due to poor design or a lack of consideration of the ASD cognitive profile, particularly at the lower functioning end of the spectrum. This article attempts to tackle the problem of the lack of design guidelines, with the aim of facilitating the development of effective educational programmes for children with severe ASD. The case study reported here evaluated two literacy educational computer programmes, by observing five low-functioning children with ASD, compared to five neurotypical children (control cases). The two types of reading-support software contrasted in the study presented different characteristics. The children's data analysed here concern observations of child-software interactive sessions based on video recordings and coded for attention deployment to each programme, including motivation and engagement indicators.