Stereotypical motor movements are one of the most common and least understood behaviors occurring in individuals with Autism Spectrum Disorder (ASD). To overcome problems with traditional methods for measuring stereotypical motor movements in persons with ASD, the Kinect sensor from Microsoft and gesture recognition algorithms were used to automatically detect hand flapping. This study provides a valuable tool to monitor stereotypes in order to understand and to cope with this problem. At the end it facilitates to identify behavioral patterns especially relevant when studying interaction skills in children with ASD.