We have developed a reduced-intensity conditioning regimen for patients with severe aplastic anemia (SAA) undergoing alternative donor transplants, which includes fludarabine (120 mg/m 2), cyclophosphamide (1200 mg/m 2) and antithymocyte globulin (7.5 mg/kg). Graft-versus-host disease (GvHD) prophylaxis consisted of cyclosporine and methotrexate. We have enrolled 38 SAA patients in this trial: median age of 14 (3–37) years, transplanted from unrelated (n= 33) or family mismatched (n= 5) donors, with unmanipulated marrow (n= 36) or peripheral blood (n= 2). Seven patients (18%) had evidence of graft failure, 11% developed grade II–III acute GvHD and 27% developed chronic GvHD. The actuarial 2-year survival is 73%, with a median follow-up of 621 days. Younger patients (⩽ 14 years) had a lower risk of rejection (5%) and improved actuarial survival (84%). Causes of death were infections (n= 3), graft failure (n= 2), Epstein–Barr virus lymphoma (n= 2) and hemorrhage (n= 2). In conclusion, the actuarial 2-year survival is encouraging in young SAA patients receiving a radiation-free conditioning regimen. The significant risk of graft failure in patients 15 years or older may require modification of the conditioning regimen in adults.