BACKGROUND: BMSCs-derived exosomes play an important role in ischemic stroke. Irisin and its precursor fibronectin type III domain-containing protein 5 (FNDC5) are implicated in neuroprotective effect. We aimed to clarify the role of exosomal irisin from FNDC5-overexpressed BMSCs in ischemic stroke. METHODS: Oxygen-glucose deprivation and reoxygenation (OGD/R) neuronal cells (HT-22 and Neuro-2a cells) model and middle cerebral artery occlusion (MCAO) mice model were established. Exosomes were isolated from FNDC5-overexpressed BMSCs (BMSCs-FNDC5-exos). Cell viability was estimated with CCK-8. Fe RESULTS: YAP, EGR1 and ACSL4 were increased in OGD/R-subjected cells. Irisin from BMSCs-FNDC5-exos elevated cell viability and suppressed ferroptosis. EGR1 transcriptionally upregulated ACSL4 and promoted OGD/R-induced ferroptosis. Additionally, YAP transcriptionally upregulated EGR1 and promoted OGD/R-induced ferroptosis. EGR1 or YAP overexpression could reverse the effects of BMSCs-FNDC5-exos. EGR1 silencing or BMSCs-FNDC5-exos overturned the facilitated ferroptosis induced by YAP overexpression, meanwhile, EGR1 silencing further enhanced the effect elicited by BMSCs-FNDC5-exos. BMSCs-FNDC5-exos reduced cerebral infarction, improved neurological impairment, inhibited ferroptosis, downregulated YAP, EGR1, ACSL4 and up-regulated irisin in MCAO mice. CONCLUSION: Exosomal irisin from FNDC5-overexpressed BMSCs improves ischemic stroke via inhibiting YAP/EGR1/ACSL4-mediated ferroptosis, which shed light on discovering new strategy against ischemic stroke.