Indications for use of influenza and pneumococcal vaccines are reviewed in view of current knowledge of the incidence, risk factors and etiology of pneumonia in adults. It appears that both vaccines contribute equally in an almost additive fashion to predicted benefits of vaccination; therefore, both should be used for maximum benefit. Target groups for vaccination include both elderly persons (e.g. 65 years and older) and younger ones who have medical risk factors that increase the likelihood or severity of pneumonia.