The aim of the present study was to investigate sustained attention and working memory in children with autism spectrum disorder (ASD), as this issue has not been widely investigated in this population. Children with ASD were age-matched with children diagnosed with dyslexia based on standardised reading assessments. All children were administered tests of working memory, IQ, and visual sustained attention. The results using a MANOVA indicated that children with ASD performed worse than children with dyslexia on verbal tests of working memory and IQ. However, their performance in the visual tests (working memory and IQ) was similar. Furthermore, correlational analyses demonstrated considerable variability in sustained attention (accuracy and errors of commission), in contrast to children with dyslexia. This pattern suggests that children with ASD may not have a deficit in sustained attention "per se." Some explanations for this attentional pattern are discussed and could be linked to their motivational framework, which means that they are less responsive to the effects of reinforcement.