Rapid changes in the demographic, political, and environmental landscape, as well as ongoing shifts in medical practice and knowledge, significantly influence the development and outcome of diseases and, consequently, how their epidemiological surveillance is conducted. To address these contextual imperatives, the Integrated Chronic Disease Surveillance System of Quebec (Sismacq) was developed by linking five medical-administrative databases covering the insured population and the health services provided to Quebecers, ranging from medical consultations to hospitalization, including medication use and ending with death. The purpose of this article is to describe Sismacq. The potential of linked data sources allows not only for determining disease prevalence and incidence but also for studying cohorts of people with diseases and analyzing health outcomes such as the burden of disease and resource utilization. This integrated approach also offers an opportunity to understand the accumulation of diseases and comorbidities. Sismacq is based on three distinct methodological steps: 1) data extraction and linkage, 2) analysis and production of indicators, and 3) dissemination. (R.A.)