Background: In a phase III trial comparing eribulin (E) vs. capecitabine (C) in pts with locally advanced or MBC, a trend for improved OS was observed but a statistically significant superiority was not demonstrated with E vs. C for OS or PFS. The AE profiles were consistent with known side effects. We now report QoL results from this trial. Methods: Pts received eribulin mesylate 1.4 mg/m² on Days 1 and 8, or C 1.25 g/m² BID orally on Days 1-14, of a 21-day cycle. Eligible pts had received prior therapy including an anthracycline and taxane, and were receiving study drug as 1^st-, 2^nd-, or 3^rd-line therapy for advanced disease. QoL, a secondary objective, was assessed using EORTC QLQ-C30 and QLQ-BR23 questionnaires at baseline, 6 weeks, 3, 6, 12, 18, and 24 months after starting treatment (or until progressive disease or treatment change), and at unscheduled visits. Longitudinal analyses were carried out using weighted generalized estimating equations adjusted for non-random attrition due to death within 12 months. Model covariates were time (visit), region, and baseline QoL. The primary endpoint was change from baseline for Global Health Status (GHS)/overall QoL; exploratory endpoints were change from baseline for each functional domain, and signs/symptoms. Results: 1,102 pts were randomized (E 554; C 548). GHS/QoL scores were low at baseline for E (56.3) and C (54.7) on a scale of 0 (worse) to 100 (best). GHS/QoL and cognitive functioning improved significantly more in pts receiving E vs. C, (6.5 [p=0.048] and 15.3 [p<0.001], respectively). Emotional functioning improved significantly for pts receiving C vs. E (3.3; p=0.033). Pain was comparable at baseline, and was lower at subsequent visits with both treatments. Patient-reported signs/symptoms in favor of E included nausea and vomiting (E1.9; p=0.043) and diarrhea (-3.7; p=0.001); systemic side effects (5.2; p<0.001) and upset by hair loss (9.3; p=0.023) favored C. Conclusions: GHS/QoL scores improved more in pts receiving E than C. E showed advantages in terms of gastrointestinal effects while C had advantages in relation to hair loss. Clinical trial information: NCT00337103.