Simultaneous scanning of multiple checks. In one example embodiment, a method for simultaneous scanning of multiple checks with a flatbed scanner includes several acts. First, a front side of a transparent sleeve is scanned on a flatbed scanner in order to create a first image. The sleeve has multiple pockets with a check positioned in each pocket. The sleeve further has multiple alignment markings on the front side and on a back side of the sleeve. Next, the back side of the sleeve is scanned on the flatbed scanner in order to create a second image. Then, it is determined from the respective positions of the alignment markings on the first image and on the second image that the sleeve was rotated between scans. Finally, one of the first and second images is automatically rotated to match the other image in order to align each front/back check image pair.