Streptococcus pneumoniae is the most common cause of both pneumonia overall and fatal pneumonia. Antibiotic resistance has developed worldwide and is most frequent in pneumococcal serotypes that are most prevalent in children (types/groups 6, 14, 19, and 23). The incidence of pneumococcal disease is the highest in children< 2 years of age and in adults> 65 years of age. Other important risk factors are chronic heart and lung disease, cigarette smoking, and asplenia. A 23-valent capsular polysaccharide vaccine and a heptavalent protein-polysaccharide conjugate vaccine are currently available. The latter is specially designed for pediatric use because small children respond poorly to polysaccharide antigens. Both vaccines are efficacious in prevention of invasive pneumococcal disease.