Background/Aim: We investigated the efficacy of neutrophil-to-lymphocyte ratio (NLR), absolute lymphocyte count (ALC), and C-reactive protein (CRP) in predicting overall survival of metastatic breast cancer patients treated with eribulin. Patients and Methods: Overall, 74 patients treated with eribulin were enrolled and their baseline levels of NLR, ALC, and CRP retrieved. Cutoff values of NLR, ALC, and CRP were set at 3.0, 1500/mu l, and 0.3 mg/dl, respectively. Overall survival (OS) was compared according to marker levels. Results: The OS of NLR-low, ALC-high, and CRP-low groups at baseline was significantly longer than that of NLR-high, ALC-low, and CRP-high groups (p=0.0027, p=0.0013, and p=0.0164, respectively). The combination of ALC and CRP was significantly associated with OS by multivariate analysis (p=0.048). Conclusion: Baseline levels of NLR, ALC, and CRP were significantly associated with OS in patients treated with eribulin. The combination of ALC and CRP improved the predictive efficacy compared to individual markers.