Fifteen patients with transfusion-dependent severe aplastic anemia (SAA) were treated with combined immunosuppression consisting of horse-antithymocyte globulin (ATG; Atgam®, Upjohn) and high-dose 6-methylprednisolone (MP). Oxymetholone was scheduled for 2 years but was discontinued in 7 patients after 10–385 days due to liver toxicity. Serious side effects usually seen in ATG monotherapy were rare during combined immunosuppression. Currently 12 of 15 patients are alive 110–1,275 days (median 475.5) after start of treatment. One patient has received too short treatment to be evaluated. All the others are transfusion-independent. Three patients died; two from septicemia before hemopoietic recovery could be expected and one after relapse. Our results confirm that (1) the addition of high-dose MP abrogates the side effects of ATG mono-therapy, and (2) the addition of MP does not counteract, but rather enhances the beneficial effect of ATG in SAA. We recommend combined immunosuppressive treatment with ATG and high-dose MP as a highly feasible, safe and effectful therapy for patients with transfusion-dependent SAA.