Provided is an immunogenic composition comprising 15 different polysaccharide-protein conjugate. Each of the conjugates comprises a capsular polysaccharide prepared from different serotype Streptococcus pneumoniae conjugated to a carrier protein, that is, serotypes 1, 2, 3, 4, 5, 6A, 6B, 7F, 9N, 9V, 14, 18C, 19A, 19F and 23F. An immunogenic composition formulated into a vaccine comprising an aluminum-based adjuvant increases the application range with respect to pneumococcal diseases in infants and children.