Background. Cancer of the trachea, bronchi, and lung is the leading cause of mortality from malignant neoplasms, at the same time being a group of heterogeneous tumors that differ in their genetic composition. In view of the availability of a drug approved in Russia with a targeted effect on KRAS G12C, the question of the number of patients with non-squamous non-small cell lung cancer (NSCLC) with the KRAS G12C mutation is relevant. Objective. Finding the estimated number of patients and the estimated prevalence of lung cancer with the KRAS G12C mutation. Methods. The authors performed a meta-analysis of 15 publications on the proportion of KRAS G12C mutations among patients with NSCLC over the past 5 years and mathematical modeling of the number of patients with KRAS G12C NSCLC in Russia, based on statistical observation data. Results. According to the meta-analysis, the proportion of KRAS G12C mutation among patients with NSCLC is 0.11 (95% confidence interval 0.10-0.13), which when extrapolating these data to the proportion of NSCLC among patients with tracheal, bronchial, and lung cancer (85%) and the number of patients with trachea, bronchi, and lung cancer who are under dispensary observation at the end of 2023 144877, the estimated number of patients with NSCLC KRAS G12C in Russia ranges from 13546 to 16009. Conclusion. The estimated number of NSCLC patients with a mutation in the KRAS G12C gene is 13.5 thousand patients (95% uncertainty interval from 12 to 16 thousand); At the same time, the prevalence of the disease is 9.3 per 100,000 population (the uncertainty range of the indicator is from 8.4 to 11.0), which makes it possible to propose it for inclusion in the register of orphan diseases.