During an outbreak caused by group A Neisseria meningitidis in March 1992, groups A and C meningococcal polysaccharide vaccine was administered to 1,168 children aged from 2 to 18 years. Parents were surveyed to ascertain reactions of children to the vaccine and development of invasive group A meningococcal disease after immunization. The most common reactions were mild local pain (21.9%), erythema (12.2%), and swelling at the injection site (7.2%). Only 1.7% of the children experienced fever and 3.7% displayed irritability. The vaccine was well tolerated and all adverse reactions disappeared within 24-48 hours of immunization. No cases of meningitis or sepsis caused by group A meningococci were seen in the 1st 12 months of observation among the vaccinated children.