A method for reproducing a document is provided. The method includes the following steps: scanning a front side and a back side of an original and accordingly producing a front side image and a back side image; determining a size of the original; comparing the size of the original with a page size; and if the size of the original is determined smaller than one half of the page size, producing one-page image data representing the front side image and the back side image on one single page. An apparatus for reproducing the document is also disclosed.