Abstract: A multi-component vaccine composition is described comprising acellular pertussis vaccine components, diphtheria toxoid, tetanus toxoid and inactivated poliovirus. The composition also may contain a conjugate of a capsular polysaccharide on Haemophilus influenzae type b and tetanus toxoid or diphtheria toxoid, which may be reconstituted from a lyophilized state by the other component. The administration of the multiple component vaccine resulted in no diminution of the immunogenicity of any component as a result of interference by other components of the vaccine.