Background: Hematopoietic stem cell transplantation (HSCT) from matched sibling donor (MSD) is the standard first-line treatment for children with severe aplastic anemia (SAA). However, the management of SAA lacking a suitable donor remains a great challenge. For those children, HSCT using unrelated donor or mismatched related donor could be a therapeutic alternative. The purpose of this study is to evaluate the outcome in children with SAA who received HSCT from donors other than matched sibling. Patients and Method: Between March 2003 and July 2009, 17 patients with SAA received HSCT from alternative donor (AD) at Asan Medical Center. We reviewed their medical records and analyzed their transplant-related parameters and outcome. Results: Of a total of 17 patients, 11 were male and overall the median age at HSCT was 9.0 years, ranging from 3.0 to 16.7 years. Four patients had Fanconi anemia and 13 had acquired SAA including 2 who developed SAA after liver transplantation. Donors included unrelated BM (U-BM) in 5, unrelated PB (U-PB) in 6, unrelated CB (U-CB) in 2 and related haploidentical PB (H-PB) in 4. Of 17 patients, 16 (94%) achieved a granulocyte engraftment at a median of 12 days post-HSCT. One patient who failed to engraft were dead despite 2nd HSCT. Of 16 with engraftment, 1 patient who received HSCT from U-CB died of severe GI GVHD and another one who received HSCT from H-PB died of pulmonary hemorrhage with late graft failure. The remaining 14 patients continue to have stable normal counts without transfusion support. With a median follow-up of 31.9 months, the Kaplan-Meier estimated overall survival at 2 years was 76.6%. Conclusion: In children with SAA, HSCT from AD including haploidentical family donor could be considered as a treatment option if the patients have no matched sibling donor.