More than a million women are diagnosed with breast cancer annually worldwide. Death from breast cancer is usually a result of chemotherapy‑resistant metastatic disease. Eribulin mesylate is a recent addition to the therapeutic armamentarium for treating locally advanced or metastatic breast cancer (MBC) in patients who have received at least two prior chemotherapy regimens for late‑stage disease. This synthetic analog, derived from a marine sponge macrolide halichondrin B, inhibits microtubule stability by blocking microtubule growth without affecting microtubule shortening. The US Food and Drug Administration has approved eribulin mesylate as a third‑line treatment for MBC refractory to anthracyclines and taxanes based on a Phase III clinical trial showing significantly increased overall survival compared to treatment of investigator’s. Asthenia, fatigue, neutropenia, alopecia, nausea, anorexia, and neuropathy are the most frequent adverse effects associated with this drug. The aim of this review was to highlight the importance of this drug in the management of breast cancer. Medline, Excerpta Medica database, cochrane database, medscape, Elsevier Scopus, and clinicaltrials.gov were searched using terms “eribulin,” “E7389,” “halichondrin,” “metastatic breast cancer.” Journal articles published from 2007 to 2012 discussing pharmacology and/or clinical trials were screened. The development of this microtubule inhibitor helps to address the need for additional effective regimens for patients progressing after standard treatment with anthracycline‑ and taxane‑containing regimens.