For selective isolation and enumeration of Streptococci including group A beta haemolytic strains. SELECTIVE STREPTOCOCCUS AGAR, MODIFIED is used for selective isolation and enumeration of Streptococci including group A beta haemolytic strains. Selective Streptococcus agar is designed and modified to inhibit gram-negative bacilli and staphylococci, thereby allowing for the isolation, subculture, and identification of pathogenic streptococci, including beta-hemolytic streptococci and S. pneumoniae. Whereas, Soya Casein Digest Agar is also used as the basal medium. Streptococcus selective agar has organic nitrogen, particularly amino acids and long-chained peptides are supplied by the combination of Casein enzymatic hydrolysate and Nucleic acid. This combination renders the medium highly nutritious. Osmotic equilibrium is maintained by Sodium chloride. Maltose is the fermentable carbohydrate energy source. Sulphate when used produces H2S. Agar is used as solidifying agent. Sheep blood (5% - defibrinated) has been added to facilitate growth and to detect hemolytic activity. Selective agents are added to suppress much of the oral flora, including coliforms, Staphylococci, Micrococcus, Haemophilus, Neisseria species and non-haemolytic Streptococci and a certain number of Enterobacteriaceae are inhibited wholly or partially, permitting satisfactory fluorescence studies of Group A.