The study was performed to evaluate the effects of influenza and pneumococcal vaccines administered alone or in combination. 124 elderly subjects living in community were vaccinated either with influenza split vaccine or with pneumococcal 23-valent or with both vaccines at the same time in different sites. Sera were tested for hemoagglutination inhibiting antibodies for influenza and for antibodies against 23-valent vaccine for streptococcus pneumoniae. No side effects were observed in the vaccinated population. Serological results indicated that influenza vaccine increased significantly antibody levels. No difference was observed between the group which received influenza vaccine alone and that which received influenza and pneumococcal vaccines associated, considering either G.M.T or the percentages of protected individuals or the percentages of subjects who seroconverted. When pneumococcal vaccine was administered at the same time with influenza vaccine, there was a not statistically significant reduction in both mean antibody concentration and mean fold increase. It is concluded that the simultaneous administration of influenza and pneumococcal vaccines to elderly individuals, including subjects at risk, is safe, effective and economically advantageous.