Background. Sentinel lymph node (SLN) biopsy is a reliable diagnostic method used to assess the spread of the malignant process in regional lymph nodes. Currently, this method is of great importance in treatment planning for early breast cancer and allows to avoid immediate and long-term complications of lymph node dissection. SLN detection can be performed using the radionuclide method, the disadvantages of which are associated with the peculiarities of working with radiopharmaceuticals and additional costs when using them. An alternative method is fluorescence lymphography (FL) with indocyanine green.Objective: performing a pharmacoeconomical study (cost-effectiveness analysis) comparing the cost-effectiveness of methods for detecting SLN in breast cancer: radionuclide diagnosis (RD) using a radiopharmaceutical based on sodium pertechnetate [99mТс] and FL using indocyanine green (Life Sciences OCPK LLC, Russia) and "IC GOR System" device (Central Design Bureau of Information and Control Systems JSC, Russia).Material and methods. The values of the cost-effectiveness ratio (CER) were calculated and compared for the two indicated methods of detecting SLN in breast cancer. Information on the RD method clinical efficacy was taken from the published data. SLN detection by the FL method with the use of indocyanine green and domestic apparatus was performed on the basis of the Regional Clinical Oncology Dispensary (Ryazan) in 53 patients with breast cancer. To assess the reliability of the obtained results a deterministic multivariate sensitivity analysis was performed.Results. The obtained CERFL values were significantly lower than the median CERRD values by average of 43.29% (p<0.001): from 40.36% (p<0.001) to 44.96% (p<0.001). The geometric mean CERFL was lower than CERRD by 39,40% (from 37.99% to 42.80%), and their 95% confidence intervals (CI) did not intersect. Deterministic multivariate sensitivity analysis demonstrated robustness of the obtained data to the transformation of RD cost parameters. Nevertheless the geometric mean and its 95% CI of CERRD and CERFL did not intersect under any circumstances.Conclusion. According to the results of a pharmacoeconomic study, it is more economically profitable to detect SLN in breast cancer using indocyanine green and a domestic device for FL, as its costs per unit of efficiency were 38–45% lower than for RD using a radiopharmaceutical based on sodium pertechnetate [99mТс].