This study examined differences in 10-year survival rates from breast cancer among white, black, and Hispanic women controlling for the effects of age, socioeconomic status (SES), stage of disease, and delay in seeking treatment for symptoms. Breast cancer patients (n = 1983) treated at M. D. Anderson Hospital and Tumor Institute in Houston, Texas between 1949 and 1968, were followed for 10 years. Ethnicity, SES, stage of disease, and delay were all found to affect survival when considered separately. Black patients were less likely to survive than either white or Hispanic patients whose survival experience appeared to be similar. Multivariate analysis that used a Cox regression technique showed that ethnic differences remained when age, SES, stage, and delay were included in the model. In contrast, the authors could not detect an effect of delay on survival when ethnicity and all other variables were included. These data suggest that ethnic differences in breast cancer survival are not mediated by differences in delay in seeking treatment for breast cancer symptoms.