Objective To evaluate the medical resource consumption due to healthcare-associated infection (HAI) in patients with tumor based on disease diagnosis-related grouping (DRG). Methods Medical records of discharged patients from a tumor center of a hospital in 2022 were analyzed retrospectively, and differences in indicators such as average length of hospital stay and average expenses per hospitalization between the HAI group and the non-HAI group were compared. Results A total of 10 674 cases were included in the analysis, and 217 cases (2.03%) were in the HAI group. The average expense per hospitalization (5.10［2.38, 8.43］ 10 000 Yuan vs 1.16［0.74, 2.04］ 10 000 Yuan) and average length of hospital stay (25 ［13, 40］ days vs 6 ［4, 11］ days) of patients in the HAI group were both higher than those in the non-HAI group, both with statistically significant differences (both P<0.05). The most common infection was bloodstream infection and pulmonary infection, accounting for 23.96% and 22.58%, respectively. In the three DRG groups, namely, RC19 (radiotherapy for malignant proliferative diseases), RU12 (supportive treatment for malignant proliferative diseases ［length of hospital stay 7-29 days］), and RB19 (high-dose chemotherapy and/or other treatments for acute leukemia), patients in the HAI group had higher average expenses per hospitalization and average length of hospital stay than patients in the non-HAI group, diffe-rences were all statistically significant (all P<0.05). Conclusion DRG assessment can effectively identify key po-pulations for HAI prevention and control, contribute to implement precise infection prevention and control strategies, and reduce HAI incidence and related medical resource consumption.