The present invention relates to polynucleotides encoding Streptococcus group C and G polypeptides and their use in immunogenic compositions. The invention also relates to immunogenic compositions comprising polypeptides encoded by those polynucleotides. In addition, the invention relates to methods of inducing an immune response in mammals against beta hemolytic Streptococcus or beta hemolytic Streptococcus infection using immunogenic compositions of the Streptococcus group C and G polypeptides and polynucleotides.