An investigation about N. meningitidis carriers was carried out in Apulia (Italy) among teen-agers. 85 healthy carriers were identified (1.4%): the 81.2% of isolates resulted polyagglutinable, 3.5% autoagglutinable and 1.2% were not classifiable with antisera. The other strains belonged to serogroup B (9.4%), W135 (2.3%), Y (1.2%) and 29E (1.2%). Some Authors report that non-groupable strains are usually isolated from healthy carriers pharynx. The most recent molecular methods permit to subdivide these bacteria in serotype and serosubtype by membrane protein antigens, too. So, today the only identification as serogroup is not able to study N. meningitidis epidemiology.