Key Points - The number of meningococcal strains received by the CNR decreased by 6.5% in 2003. - Serogroups B (58.6%) and C (31.1%) remain predominant, with a slowdown in the increase of serogroup C in 2003. - Serogroup W135 is also declining: 9.3% in 2002 and 5.9% in 2003. - Antibiotic susceptibility of meningococcal strains isolated in France is systematically assessed: resistance to rifampicin is very rare (1 resistant strain in 2003) and, apart from spiramycin, antibiotic resistance among meningococcal strains isolated in France did not increase in 2003. (R.A.)