In this paper we propose an approach which allows to define the Requirement Engineering phase of a Coopera-tive Information System (CIS). We used a notion of software engineering: the viewpoints. CIS is a complex system, it in-volves the cooperation of many stakeholders in a common purpose and each with their own viewpoint. This is why we used the notion of viewpoints, in order to decompose and partition the needs of a CIS according to the viewpoint of each stakeholder, to simplify its modeling. This approach defines a meta-model of viewpoint that will allow us to in-stance the necessary viewpoints to define the needs and re-quirements of a CIS.