OBJECTIVES: . The most common cardiac arrhythmia (atrial fibrillation, AF) increases the risk of morbidity and mortality. We estimated the health and economic consequences of the use of apixaban compared with warfarin reducing the risk of stroke in patients with AF, from the perspective of the Instituto Mexicano del Seguro Social (IMSS). METHODS: We performed a cost-effectiveness analysis using a Markov model (17 health states, six-week cycles), which simulates patients treated with warfarin (fixed dose: 5mg/day) or apixaban (10mg/day). Patients enter the model at age 70 and remain there until death (disease-related or according to Mexican life tables). Safety, efficacy and utilities were extracted from published sources. The costs of warfarin and AF-related clinical events were extracted from IMSS sources. The cost of apixaban was provided by the manufacturer. Costs are expressed in US$, 2013 and a 5% per-year discount rate was applied. Years of life and quality adjusted life years (QALYs) gained were the health outcomes. Univariate and probabilistic sensitivity analyzes were performed. RESULTS: The model estimated 7.645 life years and 5.454 QALYs in the apixaban arm, which means 0.147 and 0.160 gained life years and QALY´s, respectively (regarding warfarin). The costs of apixaban and warfarin were US$14,943 and US$15,042, respectively (apixaban is a dominant alternative). Health gains with apixaban are driven by fewer event-related deaths (10/1000 patients at risk) as well as fewer hemorrhagic strokes (12) and bleeding (13 major bleeds, 41 clinically non-major bleeds) compared to warfarin-treated patients. Treatment costs are driven by drug acquisition cost (apixaban) and monitoring cost (warfarin). CONCLUSIONS: Apixaban is more effective and safer than warfarin reducing the risk of stroke associated with AF, as well as bleeding events. To achieve this improvement, no additional economic resources need to be invested, which makes apixaban a cost-saving intervention in the context of the IMSS.