Aim: Olaparib monotherapy improves progression-free survival in patients with metastatic breast cancer and BRCA1/2 mutations. We evaluated the cost-effectiveness of BRCA1/2 mutation profiling to target olaparib use. Methods: A Markov cohort model was generated to compare the 5-year cost-effectiveness of BRCA1/2 mutation profiling to target olaparib use. Results: The incremental cost-effectiveness ratio of BRCA1/2 mutation profiling plus olaparib monotherapy was JPY14,677,259/quality-adjusted life year (QALY) (US$131,047/QALY), compared with standard chemotherapy alone. Conclusion:BRCA1/2 mutation profiling to target olaparib use is not a cost-effective strategy for metastatic breast cancer. The strategy provides minimal incremental benefit at a high incremental cost per QALY. Hence, further cost reductions in the cost of both BRCA1/2 mutation profiling and olaparib are required.