The relation between race, type of initial treatment, and survival with breast cancer were investigated using 36,905 cases reported to nine registries in the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute in the years 1978-82 and followed for survival through 1984. Using the crude treatment categories of surgical/nonsurgical/untreated, Blacks were found to have received less aggressive therapy. They were more likely than Whites to be treated nonsurgically (OR = 1.4; 95% CI = 1.2-1.7) or have no cancer-directed therapy (OR = 1.7; 95% CI = 1.3-2.3), even after adjusting by logistic regression for differences in age, stage, and histology. These treatment variables strongly affected five-year survival, after adjusting for age, stage, race, and histology. This finding of racial differences in survival-associated treatment patterns demonstrates the need to consider treatment variables in studies of race and cancer survival.