Recognizing persons from their irises is not straightforward as different types of noise can be present in the image. Indeed, the iris is located behind the cornea which is a highly reflective mirror; the resulting images could therefore be perturbed by illumination reflections. The iris is also covered by eyelids in both its upper and lower parts and partially by eyelashes. This noise is very hard to detect as it has a random form and location. Blur can also be present in the images in case of non controlled acquisition conditions. In this chapter, first research state of the art in iris recognition is presented. After in order to allowing future benchmarking, a new modular reference system called OSIRIS (Open Source for Iris) based on Daugman’s works is described. Our experiments show that the recognition module of OSIRIS outperforms Masek, another open-source software. We have defined a benchmarking protocol on a multicultural - European and Chinese - iris database and compared, Osiris, Masek and two other research systems using this benchmarking framework