The first of several cases of meningococcal meningitis was reported in April 2005, in New Delhi, India. Subsequent to this the Government declared an outbreak, which persisted for two periods, from April–July 2005 and January–March 2006. The National Institute of Communicable Diseases (NICD) recommended using WHO criteria for diagnosis of disease. During the outbreak 380 clinically suspected cases were investigated. Of 55 cases diagnosed as confirmed/probable the mortality rate was 14·6%. Meningitis was reported in 60% of cases and meningococcaemia in 40%. Microscopy of petechial rash was positive in 87·5%, CSF Gram stain positive in 68·3%, and latex agglutination test of CSF positive in 64·9% of samples. Neisseria meningitidis (serogroup A) was isolated from 37·7% of cases, 57·7% from CSF. Blood culture was positive in 10·4% of cases. CrgA polymerase chain reaction for N. meningitidis confirmed the isolates. All isolates were susceptible to third-generation cephalosporins, azithromycin and rifampicin, with increasing resistance to ceftriaxone. Penicillin resistance was encountered in 15·4% of strains. Resistance to quinolones was very high at 100% for levofloxacin, 84·6% for ofloxacin and 65·4% for ciprofloxacin. All patients with penicillin-resistant organisms (4) or intermediate sensitivity (4) succumbed to the disease. These patients also had a higher minimum inhibitory concentration to ceftriaxone.