More and more organizations are taking steps to implement management information systems, which are software programs designed to integrate and manage a set of administrative processes and data linking various functions, including financial and accounting management, sales, distribution and procurement. Despite the considerable resources often invested in the implementation of such systems, the results and impacts are often disappointing. Experience shows that one of the key conditions for a successful implementation is the effective management of the changes it entails. But how should these changes be managed? Based on a case study of the implementation by Hydro-Québec of a new customer information system and related documentation, this article proposes an intervention model that can be used by change management teams to facilitate the implementation of a management information system. We then offer key recommendations for managers and change management teams.