Background: Hospitalization consumes a large proportion of healthcare financing, and reducing avoidable admissions is critical for optimizing resource use. Objective: To determine the level of hospital admissions due to Ambulatory Care Sensitive Conditions (ACSCs) in Mongolia. Methods: Using the list of 19 ACSC groups defined by Purde et al., a quantitative analysis was conducted on 8.1 million hospital admissions recorded in the National Health Management Information System between 2014 and 2023. The main indicators included admission rates per 1,000 population, average length of stay, and average cost per admission. Results: During the study period, 759,500 avoidable admissions were identified, accounting for 13.2% of non-maternity hospitalizations. The rate of avoidable admissions was 2,375.6 per 10,000 population, with an average length of stay of 7.7 days and an average cost of 116,457.5 MNT per admission. Hypertension (42.8%) and pyelonephritis (25.4%) were the leading causes. Higher risks of avoidable admission were observed among women, the elderly, and those with lower educational attainment. Conclusion Avoidable hospitalizations impose a substantial burden on healthcare resources in Mongolia. Developing a nationally tailored ACSC list with expert consensus and implementing policies to monitor and reduce avoidable admissions are essential steps to support ongoing health sector reforms