Phenotype characterization of 11 181 invasive Neisseria meningitidis isolates collected in Brazil from 1990 to 2001 was performed. Based on laboratory data, there were 7436 (67 %) serogroup B isolates, 3391 (30 %) C, 236 W135, 51 Y, four 29E, three X, one Z, and 59 of unknown serogroup. Phenotype B : 4,7 : P1.19,15 (54 %) remained the most common during the whole of the 12-year period. Two waves were observed within the serogroup C population: the most frequent phenotype C : 2b : P1.3 (47 %) was replaced after 1998 by non-typable isolates (C : NT : NST) (16 %).