Objective To analyze the economic burden of nosocomial infections(NIs) in elderly patients, and to provide references for management strategies of NIs. Methods Retrospective method was used to collect the information of patients aged ≥60 years who had been discharged from the geriatrics department from January 1, 2017 to December 31, 2019.The propensity scoring matching method was used to conduct 1:1 case matching between the nosocomial group and the non-nosocomial group.The medical expenses of the two groups were analyzed to estimate the increased medical expenses of NIs.The indirect economic burden was estimated by calculating the economic losses of patients and their accompanying family members due to loss of working hours incurred by NIs based on the length of hospital stay.The marginal analysis method was used to estimate the economic burden of hospital caused by NIs. Results From 2017 to 2019, the total medical expenses of 372 patients developing NIs were 13,812,600 yuan, among which the increased medical expenses due to NIs were 8,883,100 yuan, accounting for 64.31% of the total expenses.Among the increased medical expenses, western medicines, antimicrobial drugs and laboratory tests were the main sources of expenses.The NIs extended the length of hospitalization by 27.00 days in 2017,16.00 days in 2018, and 19.50 days in 2019, resulting in an indirect economic burden of 2,684,800 yuan.The economic burden of the hospital due to NIs was 461,900 yuan within 3 years.The ratio of hospital profit loss due to NIs to the infection rate was about 1.83. Conclusion NIs bring heavy economic burden to patients, families, and hospitals.The cost of western medicine, antimicrobial drugs and laboratory tests could become the key breaking point in the control of direct medical costs.Real-time monitoring of NIs, timely warning of suspected cases, and reducing the incidence rate of NIs have become important strategies to reduce the economic burden.