Our study aimed at evaluation of relative survival rates of patients with high-grade breast in the United States diagnosed in 2010 using the Surveillance, Epidemiology, and End Results (SEER) Registry. We used Kaplan-Meir method to analyze the 2-year relative survival rates of 14283 Bloom-Richardson grade III breast cancer patients using SEER*Stat Program. We used Z-test to compare relative survival rates among patients' groups categorized by radiation therapy status, age groups, race, site, histology, Her2/Hormone Receptors (HR) status, and laterality using Z–test. We used Kaplan-Meir method to analyze the 2-year relative survival rates of 14283 Bloom-Richardson grade III breast cancer patients using SEER*Stat Program. We used Z-test to compare relative survival rates among patients' groups categorized by radiation therapy status, age groups, race, site, histology, Her2/Hormone Receptors (HR) status, and laterality using Z–test. There was a statistically significant increase in the 2-year relative survival rate for patients who received radiation therapy (96.8 ± 0.3%) in comparison to patients who did not receive it (89.3 ± 0.4%, P < 0.001). We also found a significant increase in the 2-year relative survival rate for age group <60 years (93.8 ± 0.3%) in comparison to age group ≥60 years (91.7 ± 0.5%, P < 0.001). When the patients were categorized according to race and tumor site, there was statistically significant differences in the 2-year relative survival rate for black patients when compared to the other races, for central portion tumors when compared to the other tumor sites, for epithelial neoplasms, NOS when compared to other histological types and for triple negative patients when compared to other Her2/HR statuses (P < 0.001). Our study results didn't show a significant difference in the 2-year relative survival rates when the cases were categorized according to the laterality of the tumor. Radiation therapy, patient's age, race, site, histology, Her2/HR status can affect the relative survival rates in high-grade breast cancer cases while laterality seems to have no effect on relative survival in such cases. These findings can be used in designing better disease surveillance and prognostic counseling programs.