Abstract: OBJECTIVE To evaluate the prevalence of hospital-associated infections (HAIs) among the hematology department patients and their economic burden based on diagnosis related groups (DRG). METHODS The patients who settled accounts based on DRG and were discharged from The First Affiliated Hospital of Soochow University between 2023 and 2024 were recruited as the research subjects, the prevalence of HAIs among the subjects was retrospectively analyzed; the direct and indirect economic burdens were compared between the patients with infections and the patients without infections among the different DRG groups by adopting the length of hospital stay, hospitalization costs and loss of labor time. RESULTS A total of 4 590 case-times of patients were enrolled in the study, with the incidence of HAIs 5.32%. The hematology department patients with infections mainly distributed in 5 DRG groups and the respiratory system (44.71%) was the major infection site. Among all the DRG group, the length of hospital stay was longer in the infection group than in the non-infection group, and the hospitalization cost of the infection group was more than that of the non-infection group (P＜0.05); there was most significant difference in the cost of drugs. The incidence of infections was highest (33.20%) and the hospitalization cost was most (284,600 yuan) in the AG19 group; the direct economic burden (1,483, 300 yuan per year) and indirect economic burden (153,300 yuan per year) due to HAIs were greatest in the RB29 group. CONCLUSIONS The hematology department patients bear the heavy economic burden due to HAIs, the patients with the allogeneic hematopoietic stem cell transplantation patients in particularly. Quantizing the economic burden of the patients based on DRG may help the medical institution to identify the high-risk disease group and achieve the precise intervention to the infection control so as to reduce the wasting of resources, reduce the burden and improve the medial quality and effect.