To clarify the existing serological varieties of Leptospira interrogans in Korea, 15 isolates of 1985 were serologically studied by cross agglutinin adsorption test. Fourteen cultures except HS 7 belonged to serogroup Icterohemorrhagiae. Isolate HM 3 and HV 8 were considered to belong to serotype mwogolo by their low residual homologous antibody(0.08 to 6.25%) after cross adsorption with serotype mwogolo referene culture and antiserum. Both residual homologous antibody of isolate HS 7 and serotype canicola reference culture remained 1.56%, accordingly HS 7 proved to belong to serotype canicola. The agglutinogens of isolate HY2, AP3, AP4, AP7 and AP9 are considered to closely related to serotype mwogolo, and HM4 and HS6 to serotype birkini, which remained to be further studied. The remaining 5 strains(HY1, HS5, HY10, 310-9, 310-19) could not be attached to any known serotype of Icterohemorrhagiae serogroup by cross adsorption test.