Iris recognition has become a popular research in recent years. Since its initial introduction by the researcher many methods have been proposed to enhance the performance. Due to its reliability and nearly perfect recognition rates, iris recognition is used in high security areas. This paper provides a review of major iris recognition researches. Iris recognition system consists of four main steps: iris localization, normalization, features extraction and iris-code matching. Comparison table of techniques of different iris recognition algorithm is also presented in brief.