Aim. To evaluate the prognostic value of pAKT1 expression by tumor cells in patients with diffuse large B-cell lymphoma.Materials and methods. The study included 90 patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL), who were treated at the clinic of Kirov Research Institute of Hematology and Blood Transfusion from 2014 to 2017 and received standard first-line polychemotherapy according to the R-CHOP regimen. Using immunohistochemical and morphometric methods, the relative number of tumor cells expressing pAKT1 was determined. Using the two-sided Fisher’s exact test, the relationship of different levels of marker expression with clinical and laboratory parameters of patients and long-term treatment results was analyzed. The impact of pAKT1 on the risk of an adverse event was assessed using the Cox regression analysis.Results. Overexpression of pAKT1 is associated with unfavorable clinical characteristics of patients with DLBCL, excessive expression of the BCL2 and c-Myc oncoproteins, as well as with low rates of overall and progressive survival. Overexpression of pAKT1 is an independent prognostic factor and statistically significantly affects the risk of an adverse outcome in DLBCL.Conclusion. The degree of pAKT1 expression is an informative criterion that allows to predict the course of diffuse large B-cell lymphoma. It is advisable to use the indicated marker when stratifying patients into risk groups.