To examine a diverse and representative population of Massachusetts women with cancer, we employed a distinctive linkage between the state's cancer registry and All‐Payers Claims Data (APCD) to assess BRCA1/2 testing among all privately‐ and Medicaid‐insured women aged ≤45 diagnosed with breast cancer in Massachusetts between 2010 and 2013. This evidence concerns the gene BRCA1 and cancer.