The streptococci, as a group, are gram positive cocci which occur in pairs or chains; they are nonmotile, nonsporing, and catalase negative. Most species are facultative anaerobes, and a few are obligate anaerobes. They are chemorganotrophs producing lactic acid as an end product of glucose metabolism. The G + C (guanine + cytosine) content reported for 15 species is 33-42% (Diebel and Seeley, 1974). The genus Streptococcus includes a large number of saprophytic, pathogenic and non pathogenic species. Many of these bacteria are members of the normal body flora. However, man is very susceptible to the pathogenic members, and no organ in the body is completely immune to streptococcal infections. As a result, streptococci cause a greater variety of clinical manifestations than any other genus of bacteria. As far as it known, no biochemical, physiological, or antibiogram pattern studies have been done on streptococci from Stockton or other parts of California. Therefore it is the purpose of this investigation to biochemically and physiologically characterize primarily extra-respiratory streptococcal isolates, study their antibiogram patterns, and relate these characteristics to each other and to other patterns reported in the United States.