We analyzed the outcome of 537 adolescents (age 12-18 years) with idiopathic aplastic anemia included in the data-base of the Severe Aplastic Anemia Working Party of the European Group for Blood and Marrow Transplantation comparing (i) matched family donor hematopoietic stem cell transplantation performed as first line treatment with (ii) front-line immunosuppressive therapy not followed by subsequent transplant given for failure and with (iii) Hematopoietic Stem Cell Transplantation performed after failed front-line immunosuppressive therapy . Overall Survival was 86% in matched family donor hematopoietic stem cell transplantation group , 90% in patients given front-line immunosuppressive alone (those who did not fail this treatment and who did not receive subsequent rescue hematopoietic stem cell transplantation) and 78% in subjects who underwent hematopoietic stem cell transplantation post failed font-line immunosuppressive therapy (p=0.14). Event Free Survival in the same groups was respectively 83%, 64% and 71% (p= 0.04). Cumulative incidence of rejection was 8% in in matched family donor hematopoietic stem cell transplantation and 9% in transplants post failed front- line immunosuppression (p=0.62). Cumulative incidence of acute graft versus host disease was 12% in matched family donor transplants and 18% in transplants post failed immunosuppression (p=0.18). Chronic graft versus host disease was higher in matched family donor hematopoietic stem cell transplantation (8%) than in transplants post failed immunosuppressive therapy (20%) (p=0.0009). Cumulative incidence of post-therapy malignancies was 0.7% in matched family donor transplantations, 7% in transplantations post-failed immunosuppression and 21% after front-line immunosuppression (p= 0.0017). In the whole cohort in multivariate analysis, the diagnosis to treatment interval of ≤2 months positively affected overall survival whereas upfront immunosuppression alone ( with no subsequent rescue transplants) negatively affected event free survival. In transplanted patients interval diagnosis-treatment ≤2 months, first line matched family donor transplants provided a significant advantage in overall and event free survival. Aplastic anemia in adolescents has a very good outcome. If a matched family donor is available, hematopoietic stem cell transplantation using bone marrow cells is the first choice treatment. If such a donor is not available, immunosuppressive treatment may still be an acceptable second choice also because in case of failure, hematopoietic stem cell transplantation is a very good rescue option.