Introduction: Lung cancer is the leading cause of cancer-related deaths in the world, and half of all new cases (59.6%) are recorded in Asia. Smoking remains the leading cause of death from lung cancer and COPD, followed by air pollution. Therefore, in Ulaanbaatar, where the population concentration is high and air pollution is high, there is a need to study the new cases and deaths of lung cancer in detail. Purpose: It is aimed to evaluate the prevalence of new cases and deaths of lung cancer among the population of Ulaanbaatar. Materials and Methods: This study analyzed new cases and deaths diagnosed with lung cancer from 2013 to 2023 in the city of Ulaanbaatar using a single-moment design of descriptive research. The quantitative data of the study included the diseases recorded using the International Classification of Diseases X (ICD-10) and lung cancer codes C-33 and C-34. The numerical data collected during the research were processed in the Microsoft Office Excel-13 program and processed using the IBM SPSS Statistics 23 program. Results: A review of the newly registered lung cancer epidemic in Ulaanbaatar from 2014-2022 has observed an increase in the number of new cases recorded in Songinokhairkhan, Sukhbaatar, Khan-Uul, and Baganuur districts in those years and in recent years in the Bayanzurkh and Sukhbaatar districts. Men were three times more likely than women to develop lung cancer, with new cases and deaths highest in the 55-69 age group. The cancer diagnosis was diagnosed using imaging devices. Of the total cases diagnosed, 9 out of every 10 people diagnosed are diagnosed later, or 3.4 per cent, and 69.5 per cent are diagnosed with jumping stages. Conclusion Although the number of new cases and deaths among the population of Ulaanbaatar is relatively lower than the national average, there has been an increasing trend in recent years.