The invention relates to immunogenic polysaccharide-protein conjugates comprising a capsular polysaccharide (CP) from Streptococcus agalactiae, commonly referred to as group B streptococcus (GBS), and a carrier protein, wherein the CP is selected from the group consisting of serotypes Ia, Ib, II, III, IV, V, VI, VII, VIII, and IX, and wherein the CP has a sialic acid level of greater than about 60%. The invention also relates to methods of making the conjugates and immunogenic compositions comprising the conjugates. The invention also relates to immunogenic compositions comprising polysaccharide-protein conjugates, wherein the conjugates comprise a CP from GBS serotype IV and at least one additional serotype. The invention further relates to methods for inducing an immune response in subjects against GBS and/or for reducing or preventing invasive GBS disease in subjects using the compositions disclosed herein. The resulting antibodies can be used to treat or prevent GBS infection via passive immunotherapy.