The article describes the respective value of data from various cancer surveillance systems, as well as from systems for which cancer surveillance is not the primary objective, for evaluating cancer control strategies. Specific insights are provided regarding cancers linked to environmental and occupational factors. The long-standing and comprehensive system for recording causes of death enables a spatio-temporal analysis of cancer mortality. Based on registry data, which cover approximately 20% of the population, trends in national and regional incidence estimates are published regularly. Survival studies and publications on incidence by prognostic factors contribute to the assessment of the impact of cancer screening. Data from the Medical Information Systems Program (PMSI) and long-term illness (ALD) registrations for cancer complement the previous system by identifying recent breaks in trends and by producing incidence estimates at the departmental level. Future plans focus on developing, at the national level and in addition to the registries—which remain the standard—a multi-source cancer surveillance system (SMSC) with automated cross-referencing of data from ALD, PMSI, and shared oncology records. Pending the implementation of this system (within at least 5 years), the cross-referencing of the PMSI and ALD databases is under consideration. (R.A.)