OBJECTIVES: Breast cancer is the most common malignant tumor and accounts for the most number of cancer-related deaths in Russian women. Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors ribociclib and palbociclib, both in combination with aromatase inhibitors, are approved for the 1^st line treatment of postmenopausal women with HR-positive HER2-negative advanced breast cancer in Russia, however no CDK4/6 inhibitor is included in the Russian Vital and Essential Drug list (VEDL). The aim of the current study is to conduct budget impact analysis of ribociclib and palbociclib for the 1^st line treatment of HR-positive HER2-negative advanced breast cancer from the Russian healthcare system perspective. METHODS: We proposed partitioned survival model of breast cancer progression on ribociclib + letrozole (hereafter referred to ribociclib) and palbociclib + letrozole (hereafter referred to palbociclib). Overall and progression-free survival on ribociclib were modeled using MONALEESA-2 trial results. Survival functions for palbociclib were obtained with proportional hazard model and results of matching-adjusted indirect comparison (MAIC) of ribociclib vs palbociclib. Time horizon of the model was 5 years, as proposed by the Russian guidelines for pharmacoeconomic research. We considered costs that included 1^st and subsequent lines of drug therapy, adverse events treatment, inpatient and outpatient care. RESULTS: Despite similar (no statistically significant difference) PFS and OS profile, 5-year total per patient costs on ribociclib were US$80,076, which were US$18,653 or 19 % less than for palbociclib. Lower costs on ribociclib are driven by less monthly medication costs and potential of cost reduction due to dose reduction. If 8 200 women start treatment with ribociclib annually, healthcare budget will save US$322 million, compared to treatment with palbociclib. CONCLUSIONS: Ribociclib is a cost-saving technology that could be recommended for inclusion into VEDL in Russia.