OBJECTIVES: To evaluate healthcare resource utilization and costs among patients diagnosed with breast cancer in the Medicaid program.  METHODS: Patients diagnosed with breast cancer (International Classification of Disease, 9^thRevision, Clinical Modification [ICD-9-CM] diagnosis code 174, 233.0, 238.3, 239.3) were identified using Medicaid data from January 1, 2008 through December 31, 2010. The initial diagnosis date was designated as the index date. Patients without breast cancer (comparison cohort) who were the same age, race, and gender were identified and matched. A random index date was chosen to minimize selection bias. Patients in both cohorts were required to be at least age 18 years, with continuous medical and pharmacy benefits 1-year pre- and 1-year post-index date. One-to-one propensity score matching (PSM) was used to compare healthcare costs and utilizations during the follow-up period, between the diseased and comparison cohorts, and adjusted for baseline demographic and clinical characteristics.  RESULTS: After risk adjustment by PSM, a total of 19,079 patients in each cohort were matched. Significantly more breast cancer patients had inpatient admissions (23.77% vs. 12.56%, p<0.0001) and long-term care (7.77% vs. 6.60%, p<0.0001), other service (99.88% vs. 87.86%, p<0.0001) and pharmacy visits (77.80% vs. 68.85%, p<0.0001), compared to those without breast cancer. Breast cancer patients also incurred significantly higher inpatient ($2,141 vs. $1,537, p<0.0001), long-term care ($7,471 vs. $5,335, p<0.0001), other service visit ($23,592 vs. $14,780, p<0.0001) and pharmacy costs ($3,379 vs. $2,787, p<0.0001) compared to those in the comparison cohort.  CONCLUSIONS: Breast cancer patients in the Medicaid program incurred substantially higher healthcare resource utilization and costs compared to those without the disease.