BACKGROUND: Allogeneic stem cell transplantation (alloSCT) reduces relapse rates in acute leukemia, but outcome is hampered by toxicity. Population-based data avoid patient selection and may therefore substitute for lack of randomized trials. METHODS: We evaluated alloSCT rates within the Swedish Acute Leukemia Registry, including 3899 adult patients diagnosed from 1997 through 2006 with a coverage of 98% and a median follow-up of 6.2 years. RESULTS: AlloSCT rates and survival decreased rapidly with age >55 years. The 8-year overall survival (OS) was 65% in patients <30 years and 38% in patients <60 years and was similar for acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Among 1073 patients <60 years, alloSCT was performed in 42% and 49% of patients with AML and ALL, respectively. Two-thirds of the alloSCTs were performed in first complete remission, and half used unrelated donors, the same in AML and ALL. Regional differences in management and outcome were found: 60% of AML patients <40 years received alloSCT in all parts of Sweden, but two-thirds of AML patients 40-59 years had alloSCT in one region compared with one-third in other regions (P<.001), with improved 8-year OS among all AML patients in this age cohort (51% vs 30%; P = .005). CONCLUSIONS: More Swedish AML patients received alloSCT, and long-term survival was better than in recently published large international studies, despite our lack of selection bias. There was no correlation between alloSCT rate and survival in ALL. In adult AML patients <60 years of age, a high alloSCT rate was associated with better long-term survival, but there was no such correlation in ALL. Cancer 2011;. © 2011 American Cancer Society.