An Inter-Organizational Business Process (IOBP) is an organized group of joined activities carried out by two or more organizations to achieve a common business objective. A consequence of this is that business process modeling and design used inside an organization have to be enhanced and extended to cope with inter-organizational business particularities. Thus, methods are required to describe and automate inter-organizational business processes in an efficient manner. Modeling IOBP involves new challenges, mainly the ability to cope with autonomy, privacy, heterogeneity, and the support for coordination trough mutual agreements. As a contribution to this area, this paper proposes a framework for IOBP modeling based on MDA approach which relies on the principles of SOA.