The Wisconsin Card Sorting Task (WCST) is the only cognitive flexibility task that has consistently shown deficits in individuals with an autism spectrum disorder (ASD). As this is the only task characterized by limited explicit task instructions and a high degree of disengagement required to perform the switch, we hypothesized that cognitive flexibility deficits of individuals with ASD might only become apparent in situations fulfilling these requirements. However, the WCST involves various additional cognitive processes besides switching, making it uncertain whether difficulties are indeed due to cognitive flexibility impairments. The aim of this study was to investigate whether individuals with ASD show cognitive flexibility impairments on a more controlled task-switching variant of the WCST, still fulfilling both requirements. We therefore developed such a task and administered it to 40 high-functioning children with ASD and 40 age- and IQ-matched typically developing controls. As predicted, individuals with ASD made more perseveration errors and had a significantly higher switch cost than typically developing controls, but they performed equally well on the control measures. (Contains 4 figures and 3 tables.)