User verification systems that use a single source of biometric information are not sufficient to meet today’s high security requirements for applications. This is because these systems have to contend with noisy data, intra-class variations, spoof attack and non-universality. Therefore, there is need for employing multiple sources of biometric information to provide better recognition performance as compared to the systems based on single trait. This paper is an overview of different categories of multibiometric systems, information fusion in multibiometric systems, and approaches to feature fusion at feature selection phase.