Invasive meningococcal infections (IMIs) are among the diseases that must be reported to health authorities. Initially, all suspected cases must be reported without delay to the Departmental Directorate of Health and Social Affairs to enable the rapid implementation of control measures among contacts... The information collected each year makes it possible to describe the disease and study its trends over time. This article summarizes the key points of the descriptive analysis of the 2000 data, which will soon be published by the InVS in "National Surveillance of Infectious Diseases: 1998–2000," and the initial findings emerging from the provisional 2001 data. These provisional 2001 data as of May 2, 2002, report 677 weekly reports (new criteria) and 558 notification forms received (old criteria). The incidence rate of meningococcal infections has been gradually increasing since 1996 but remains well below the rates recorded in the 1980s. This increase is due, in part, to improved reporting by clinicians, with the completeness rate rising from 62% in 1996 to 73% in 1999. It also reflects a real increase in the number of cases. (adapted from the text)