Purpose -The purpose of this paper is to identify the factors associated with the successful implementation of a shared interlibrary loan (ILL) system by the Ontario Council of University Libraries (OCUL), a consortium of 20 Ontario universities.Design/methodology/approach -The paper is a descriptive review of the approaches taken in the consortial implementation of OCLC's VDX software. The paper elaborates on the buildingblocks and barriers to success as they were experienced, first by participants in OCUL's centralized implementation activities, and second at the local level by staff at Ryerson University Library, a member institution. Now end users can simultaneously search world-wide catalogues, submit and track progress of requests, and receive materials rapidly. System functionality includes auto-mediated interlibrary loans (direct requesting); use of link-resolver software to transfer citation information from borrowing library catalogues to ILL request forms; and ISO peer-to-peer messaging.Findings -Post-implementation analysis reveals several key factors that contributed to the project's success. These include: planning, leadership, financial support, technical support, cooperation, staff commitment, communication, staff-and end-user centered focus, training and evaluation.Practical implications -This may have broad application for similar complex projects.Originality/value -The OCUL VDX implementation has achieved the originally expected economies of scale, service performance improvements and reduction in localized maintenance and system support. However, there have also been several unforeseen benefits such as the After three years of envisioning, planning, and preparation, OCUL libraries started implementing in the summer of 2003. Implementation was phased across OCUL over a two and a half year period during which time the project has passed several milestones. In September 2005, the French version of the public interface was launched. In 2006-2007 several member-libraries moved from staff-mediated to auto-mediated interlibrary loans (direct requesting), which frees up time for staff to handle more difficult requests. More recently, libraries are using link-resolver software (see Appendix) to transfer citation information from borrowing library databases to ILL request forms. As of May 2008, the introduction of Jasper Reports allows local ILL Managers to generate ILL and Collection Development statistical reports on demand and in real-time or on a fixed schedule. The consortium continues to broaden its reach by implementing ISO peer-to-peer messaging beyond the OCUL network. As of July 2008, more than 2.6 million requests had been processed since 2003.In the case of Ryerson University, participation in the OCUL interlibrary loan initiative has enabled the Ryerson Library to obtain a resource that could not be developed or maintained locally. Participating in the RACER project provides users with software, expanded services, gave staff opportunities for cooperation and networking, and easy access to r...