Background: Problems with social functioning are a major area of difficulty for children with autism. Such problems have the potential to exert a negative influence on several aspects of the children's functioning, including their ability to access education. This study looked to examine if a computer-based activity program could improve the social functioning of these children. Materials and Methods: Using a pooled subject design, 100 children with autistic spectrum disorder were randomly allocated, controlling where possible for age and gender, to either an intervention or a control group. The children in the intervention group were encouraged to use the Nintendo (Kyoto, Japan) Wii™ and the software package “Mario & Sonic at the Olympics” in addition to their routine school physical education classes over a 9-month period. The control group attended only the routine physical education classes. Results: After 1 year, analysis of the changes in the scores of teacher-completed measures of social functioning showed that boys in the intervention group had made statistically significant improvement in their functioning when compared with controls. The number of girls in the study was too small for any change to reach statistical significance. Conclusions: This type of intervention appears to have potential as a mechanism to produce improvement in the social functioning, at least of boys, as part of a physical education program.