Recurrence of disease after Haemophilus influenzae bacteremia is relatively uncommon and may often be preventable. Three previously unreported and 11 reported occurrences in ten patients were evaluated in regard to pathogenesis. Recrudescence can be prevented by adequate culturing prior to therapy, proper treatment based on complete sensitivity testing and pharmacologic principles, and careful evaluation of clinical and microbiologic response. Relapse may be prevented in some instances by administering prophylactic rifampin to patients and close contacts who may be carriers of an infecting strain. Reinfections may be prevented through public health measures and the development of effective vaccines.