OBJECTIVES: Erythropoietin stimulating agents (ESAs) are useful drugs for treating chemotherapy related anemia to reduce the number of blood transfusions. However, there were unrecognized toxicities of ESAs. These toxicities were finally recognized in 2007 when the FDA issued a black box warning for ESAs. The objective of this study is to determine the effect of the FDA black box warning on ESA use patterns and associated outcomes in insured, low -income cancer patients in South Carolina. METHODS: The merged South Carolina Central Cancer Registry-Medicaid dataset was used to determine the trend of ESA use from 2001-2010. Female Breast, Colorectal and Non-Small Cell Lung cancer patients were identified from the registry. Of those, their chemotherapy status was identified along with ESA use from Medicaid medical claims. The major outcome measures were claims for use of ESAs after chemotherapy and the blood transfusion rate.  Logistic regression was used as a quantitative method to determine if the likelihood of receiving ESA treatment was reduced after FDA black box warning. RESULTS: Among 1,645 patients treated with chemotherapy from 2002-2010, the proportion of chemotherapy patients receiving ESAs decreased from 56.47 % before the black box warning to 23.16% after black box warning (p < 0.001). The blood transfusion rate per year during 2002-2007 remained around 10-15% and increased to 31% in 2009. The likelihood of ESA use was reduced by 63% after black box warning issued by FDA after adjusting for demographic and clinical variables. CONCLUSIONS: The black box warning may have been effective in reducing overall ESA utilization in cancer patients taking chemotherapy.