8 patients with severe and 4 with non-severe aplastic anaemia, aged 7 to 46 years, whose suppressor lymphocyte activity was in most cases elevated and who had no histocompatible sibling donor, underwent 1-2 courses of ALG/ATG treatment. 6 patients got CR and 1 PR and during 1-4 years they live with sustaining haemopoiesis, independent of blood transfusion (except one in PR). Among these seven responders increased suppressor lymphocyte activity normalized in 6. The adverse effects of the treatment were granulocyto- and thrombocytopenia, subfebrile states, hepatotoxicity, serum sickness and skin allergy. Five patients died because of early or late complications of the treatment or it's failure. Our results, similar to other authors', are like after BMT and supports the immunological mechanism of A.A. Immunosuppressive treatment with ALG/ATG has many advantages: no need to have identical bone marrow donor, no GVHD, possibility of treatment of patients over 30, even pretreated with blood transfusions, and finally much lower costs and efforts.