Abstract: Systems and methods for injecting secondary images into viewing fields of surgical microscopes are disclosed. Some exemplary embodiments may provide secondary image injection in a picture-in-picture arrangement, thereby allowing a surgeon to simultaneously view the one or more secondary images and the surgical field through the oculars of the surgical microscope. Some exemplary embodiments may allow injection of secondary images including live video, such as live images from an endoscope, as well as previously obtained images, such as stored images from pre-operative studies.