Decentralization and openness are inherent properties of multi- agent systems (MAS). The technologies they provide are thus the right abstrac- tion for developing Web-oriented applications. Moreover, di erent works have been proposed to use Semantic Web technologies (SWT) for representing vari- ous dimensions of MAS (e.g., interaction protocols, norms, organizations). Given these facts, we think it is time to go a step further by integrating SWT and MAS in order to improve reusability of data, knowledge, coordination strategies, etc. on the Web and across systems. In this paper, we take a rst step in this direc- tion by proposing a semantic description of multi-agent organizations, showing the bene t regarding integration with Web ontologies.