The principal characteristics of monoclonal antibodies (MCA) ICO have been presented. The MCA ICO panel includes MCA against differentiating antigens of T- and B-lymphocytes, myelomonocytes, human leukemia-associated antigens. The following MCA have been described: MCA ICO-87 against common T-cell antigen CD7, ICO-33 and ICO-80 against common T-cell antigen CD5, MCA ICO-10 against Thy-1 antigen of early thymocytes, ICO-44 against CD1c antigen of cortical thymocytes, MCA ICO-90 against CD3 antigen of mature T-lymphocytes, MCA ICO-86 against CD4 antigen of T-helper/inductor cells, MCA ICO-31 against CD8 antigen of T-suppressor/cytotoxic cells, MCA ICO-1 against nonpolymorphic antigens of HLA II class, MCA ICO-12 against CD22 antigen of B-lymphocytes, MCA ICO-30 against mu-chain of human IgGM, MCA ICO-66 against CD37 antigen of B-lymphocytes, MCA ICO-88 against antigen of activated T- and B-cells, MCA ICO-35 against lymphoblasts, MCA ICO-88 against CD38 antigen of thymocytes and activated cells.