Aim. To evaluate the impact of additional chromosomal aberrations on outcomes of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with acute myeloid leukemia (AML) with t(8;21)(q22;q22)/RUNX1-RUNX1T1 translocation. Methods. Twenty-five AML patients with t(8;21)(q22;q22)/ RUNX1-RUNX1T1 translocation (10 women and 15 men, aged from 2 to 58 years; median 20.2) were examined. Analysis of overall (OS) and event-free survival (EFS) predictors after allo-HSCT in patients with different clinical, transplant and cytogenetic characteristics was performed. Results. The additional cytogenetic abnormalities were found in 13 (52 %) patients before the transplantation, at that, complex karyotype with three or more chromosomal abnormalities were registered in 9 (69 %) patients. The univariate analysis showed that OS and EFS after allo-HSCT differed in patients with different characteristics such as age (p = 0.03; p = 0.0006), clinical status at transplantation (p = 0.0002; p = 0,006), donor type (p = 0.0003; p = 0.002), the interval from diagnosis of leukemia to allo-HSCT (p = 0,008, for OS only), additional cytogenetic abnormalities (p = 0.03; p = 0.009) and complex karyotype (p = 0.004; p = 0.0003), respectively. In multivariate analysis, independent predictors of OS were donor type (p = 0.01), the interval from diagnosis of leukemia to allo-HSCT (p = 0.01), and additional cytogenetic abnormalities in karyotype (p = 0.04), as well as donor type (p = 0.04) and patient’s age (p = 0.004) for EFS. Conclusion. AML with t(8;21)(q22;q22)/RUNX1-RUNX1T1 translocation is a heterogeneous disease. The prognosis in patients with the additional cytogenetic abnormalities, especially in those with the complex karyotype, is worse both after the standard chemotherapy (i.e. before allo-HSCT), and after allo-HSCT.