Abstract This study introduces a novel iris localization method based on the competitive chords. The new method can be used to detect pupil–iris and iris sclera boundaries. The basic idea is to construct a set of chords from the left edges and the right edges of the pupil (or iris), and then find the winner chords with aligned centers. The winner chords can be used to vote to the correct pupil’s (or iris’s) center and radius. To verify the effectiveness of the proposed method, it is compared with two efficient techniques and applied to five datasets. The experimental results show that the new method is faster,more accurate and more robust than the state-of-theart iris localization methods.