Background: Socioeconomic status (SES) and race are major determinants of health outcomes in the United States. We aim to assess the effect of SES as measured by the Neighborhood Deprivation Index (NDI) and race on outcomes in metastatic breast cancer patients at our center. Methods: The NDI scores for patients with metastatic breast cancer who were treated at our center between 2000 and 2017 were obtained from the Neighborhood Atlas using their Zip-Code (N = 1246). The SES groups were defined as low deprivation with an NDI score in the bottom tertile and high deprivation with NDI in the top or middle tertiles. Baseline characteristics were compared between the SES groups with Bonferroni correction. Univariate and multivariate survival analysis were performed using the R packages “survival” and “survminer”. Results: Race was the only baseline characteristic that was significantly different between the SES groups, the high deprivation group had a higher proportion of African Americans (10.5%) than the low deprivation group (3.7%, P = 9.3e-05). In univariate Kaplan-Meier survival analysis, both SES and race had significant effect on overall survival such that the high deprivation group had worse survival than low deprivation (Log Rank P = 0.01) and African Americans had worse survival than Caucasians (P = 0.008). In multivariate Cox proportional hazard model, SES, but not race, had a significant effect on overall survival (hazard ratio for high deprivation was 1.19 [95% Confidence interval 1.04 - 1.37], P = 0.01; Table). Progression-free survival on first-line chemotherapy was not different between the SES groups or racial groups in both univariate and multivariate analysis. Conclusions: The current study shows that patients from the high deprivation group (i.e., low SES), have worse survival in metastatic breast cancer. Race was no longer a significant predictor of survival when SES was accounted for in the analysis. This possibly suggests that poor outcomes in the African American population is explained by the association between low SES and African American race. Based on these results, there is an urgent need for healthcare investments in the low SES neighborhoods.