OBJECTIVES: A significant proportion of patients with hormone receptor positive (HR+) early-stage breast cancer (ES-BC) are not benefiting from the adjuvant chemotherapy, which is associated with adverse events and substantial costs. Thus, it is important to develop high-quality methods to assess the cost-effectiveness of pharmacogenomics tests that identify who are most likely to benefit from adjuvant chemotherapy. This study aims to develop a global economic model for pharmacogenomics tests in ES-BC. METHODS: A literature review was conducted to identify economic evaluations of pharmacogenomics tests used in BC to identify key assumptions and parameters for the development of the global economic model, which includes a decision tree and a partitioned survival model. The economic impact of new tests for treatment of ES-BC could be assessed from a provincial Ministry of Health (MoH) or a societal perspective over up to a lifetime horizon. Survival curves and recurrence risk were extracted from clinical trials, while utilities were obtained from literature. Direct costs (genetic test, treatment acquisition, resource utilization, administration, follow-up) and indirect costs were obtained from literature and governmental publications. The model was tested using the Oncotype Dx test, which determines the individual risk of recurrence and identifies the likelihood of benefits from chemotherapy, compared to no testing. RESULTS: Over a 12-year period, the model leaded to incremental cost-utility ratios (ICURs) of $69,162$/QALY and $27,595/QALY when tested, from a MoH and a societal perspective, respectively. Results were similar to those obtained in the literature. According to deterministic sensitivity analyses, parameter with the greatest impact on base-case ICURs was the recurrence risk. CONCLUSIONS: Personalized medicine is increasingly used in oncology, particularly in breast cancer, where new tests/treatments are introduced into the Canadian health system every year. The developed model could be of great help in achieving uniform economic evaluations to Canadian health technology agencies.