The development of multivalent pneumococcal vaccines for the prevention of both systemic and noninvasive pneumococcal diseases in infants, older adults, and immunecompromised individuals has gained increasing importance over the last decade. The rising cost of medical care has renewed interest in prevention instead of cure for a disease and in many cases cures may not be available with the increase in antibiotic resistance in many bacteria. Capsular Polysaccharide vaccines for the prevention of systemic pneumococcal disease in adults and older children have been readily available for over 17 years but use of the vaccine in these age groups has been limited. The recent licensures of Hib-protein conjugate vaccines, 1987 for toddlers, 1990 for infants, have contributed to a dramatic reduction in the incidence of invasive Haemophilus influenzae type b disease and have thus demonstrated the tremendous potential of this technology to significantly reduce the incidence of diseases caused by encapsulated bacteria.