Using the PHA method, streptococcal type-specific antibody was studied in sera from 230 patients with various types of nephritis diagnosed by renal biopsy in order to clarify the relationship between streptococcal infection and the histological types of glomerulonephritis. Two or more serologic types of streptococcal type-specific antibodies with high titers (1:384 or more) were significantly increased in patients with MGA, FGS, PGN, endocapillary proliferative GN, MPGN and IgA GN as compared with those in healthy subjects. Two or more serologic types having high titers (1:384 or more) were significantly increased in MGA, PGN, MPGN and IgA GN as compared with MN. The highest titers (1:768 or more) of streptococcal type-specific antibodies were significantly more frequent in endocapillary proliferative GN as compared with healthy subjects, and such titers were significantly increased in endocapillary proliferative GN and MPGN as compared with MN. The frequency of detection of streptococcal serologic types having high titers (1:384 or more) as found in patients with various nephritis, was in the order of Types 18, 3, 30, 1, 12, 10, 6 and 37, and more than half of the nephritogenic types were included in these serologic types. The above data, which suggest a higher probability of contact with nephritogenic strains during alternative establishment of streptococci by different serologic types, may indicate a close relationship of streptococcal infections with MGA, PGN, MPGN, IgA GN, FGS and endocapillary proliferative GN.