Abstract Background Genomic tests are a useful tool for adjuvant chemotherapy decision‐making in the case of hormone receptor‐positive (HR+), and human epidermal growth factor receptor 2‐negative (HER2−) breast cancer with intermediate prognostic factors. Real‐life data on the use of tests can help identify the target population for testing. Methods French multicentric study (8 centers) including patients, all candidates for adjuvant chemotherapy for HR‐positive, HER2‐negative early breast cancer. We describe the percentage of tests performed outside recommendations, according to the year of testing. We calculated a ratio defined as the number of tests required to avoid chemotherapy for one patient, and according to patient and cancer characteristics. We then performed a cost‐saving analysis using medical cost data over a period of 1 year from diagnosis, calculated from a previous study. Finally, we calculated the threshold of the ratio (number of tests required to avoid chemotherapy for one patient) below which the use of genomic tests was cost‐saving. Results A total of 2331 patients underwent a Prosigna test. The ratio (performed test/avoided chemotherapy) was 2.8 [95% CI: 2.7–2.9] in the whole population. In the group following recommendations for test indication, the ratio was 2.3 [95% CI: 2.2–2.4]. In the case of non‐abidance by recommendations, the ratio was 3 [95% CI: 2.8–3.2]. Chemotherapy was avoided in 841 patients (36%) following the results of the Prosigna test. The direct medical costs saved over 1 year of care were 3,878,798€ and 1,718,472€ in the group of patients following test recommendations. We calculated that the ratio (performed test/avoided chemotherapy) needed to be under 6.9 for testing to prove cost‐saving. Conclusion The use of genomic testing proved cost‐saving in this large multicentric real‐life analysis, even in certain cases when the test was performed outside recommendations.