— Active databases have been used in many different fields to accomplish many different tasks. One of the main problems today that still have not been solved is authorization. In some situations it is enough that user knows e.g. password, in other situations it is enough that user posses e.g. a smart card, but, there are also situations where user’s unique physical or psychological characteristics need to be measured. In this paper we are going to put accent on this third possibility. We will show how the concept of complex events presented in the active database theory could be used in order to build a multimodal biometric system. Especially, we will explore the paradigm of active rules and complex events, and apply them in order to implement a multimodal biometric system.