A study was made of the biochemical profiles of 59 strains serotyped as Streptococcus suis, isolated from diseased and clinically healthy pigs. The following parameters are proposed for the identification of the species: Voges-Proskauer negativity, hydrolysis of esculin positivity, trehalose positivity, negativity for growth in 6.5% NaCl, and absence of beta-hemolysis on sheep blood agar. S. suis serotype 2 is negative for hippurate, pyrrolidonylarylamidase, and mannose.