A Multi-Source Information System (MSIS), has been designed for the Renal Epidemiology and Information Network (REIN) dedicated to End-Stage Renal Disease (ESRD). MSIS aims at providing reliable follow-up data for ESRD patients. It is based on an n-tier architecture, made out of a universal client, a dynamic Web server connected to a production database and to a data warehouse. MSIS is operational since 2002 and progressively deployed in 9 regions in France. It includes 11,500 patients. MSIS facilitates documenting medical events which occur during the course of ESRD patient' health care and provides means to control the quality of each patient's record and reconstruct the patient trajectory of care. Consolidated data are made available to a data warehouse and to a geographic information system for analysis and data representation in support of public-health decision making.