Background: Tuberculosis (TB) remains a major public health concern worldwide and continues to be a leading cause of morbidity and mortality. Delays in diagnosis and care seeking exacerbate disease severity and increase financial burdens on healthcare systems and patients. In Mongolia, comprehensive evidence on diagnostic delays and direct hospitalization costs for TB patients remains limited. Aim: To evaluate the duration of diagnostic delay and estimate direct medical costs incurred during hospitalization among TB patients, as well as to identify associated factors. Materials and Methods: A retrospective cross-sectional study was conducted using medical records of 285 newly diagnosed TB patients hospitalized at the National Center for Communicable Diseases (NCCD) in 2024. Statistical analyses were performed using SPSS version 26 and MS Excel. A p-value of <0.05 was considered statistically significant. Result: The mean age of participants was 42.6±16.0 years, and 56.5% (n=161) were male. Median patient delay was 14 days (IQR: 5–31), median diagnostic delay was 4 days (IQR: 0–14), and mean hospital stay was 21.0±16.0 days. Median direct costs per patient were: diagnostic cost 262.0 thousand MNT (IQR: 187.0–363.0), treatment cost 490.9 thousand MNT (IQR: 234.4–884.1), and total cost 761.7 thousand MNT (IQR: 460.4–1247.6). Multivariate linear regression revealed that patient delay >14 days was significantly associated with higher total costs (=659.333, p=0.004). Conclusion 1. The median patient delay among patients with tuberculosis was 14 days (IQR, 5–31), while the median diagnostic delay was 4 days (IQR, 0–14). Overall, 61.6% of patients experienced patient delay, and 63.5% experienced diagnostic delay. 2. The median total direct medical cost among hospitalized patients was 761.7 thousand Mongolian Tugriks (MNT). A patient delay of more than 14 days was significantly associated with increased total direct medical costs (β=659.333, P=.004).