We report seven cases of influenza-associated deaths in persons under twenty-two years of age, five of whom were previously fit and well, during an influenza A epidemic affecting Auckland city during the second quarter of 1979. Despite intensive care in three of the patients, all followed a similar course of fatal hypoxaemia. The failure of appropriate therapy in those patients with staphylococcal superinfection was a further feature. Influenza A-subtype H1N1 was isolated from throat swabs and/or post-mortem lung in five of the cases. This subtype has not been responsible for epidemic influenza or influenzal outbreaks in New Zealand since the early 1950s. The isolates were most similar to the A/Brazil/11/78 strain which has not previously been isolated in New Zealand. The susceptibility of young people is attributed to lack of previous antigenic exposure in those born since the mid-1950s.