Background: To evaluate the impact of Oncotype DX as a tool for adjuvant treatment decision of ER-positive, early stage breast cancer patients diagnosed in Kuwait and to determine which clinicopathological criteria derived the greatest advantage Methods: This retrospective study was designed to review patients with ER-positive, HER2−negative, stage I–IIIA, N0/N1 breast cancer who were tested for Oncotype Dx and treated in Kuwait Cancer Control Center. We used McNemar test to assess the association of Recurrence Score results with the changes in the treatment decisions. Results: Between January 2011 and October 2017, 100 patients at a median age of 50 years (range 38-74 years) were included. The TNM stage distribution was 34, 63 and 3 patients for stage I, II and IIIA respectively. Ki67 was available in 89 patients, 51 had Ki67 ≤ 15% and 38 patients had Ki67 > 15%. Fifty-four patients had Luminal A and 46 had luminal B tumors. The Recurrence Score results were low, intermediate and high risk in 54, 34 and 12 patients respectively. Before the test results, adjuvant chemoendocrine therapy was recommended for 46 patients while 54 were advised for endocrine therapy, according to the multidisciplinary team consensus. After getting the test results, 25 patients received chemoendocrine therapy (1,12 and 12 patients in the low, intermediate and high risk groups respectively) and 75 received endocrine treatment. Treatment change was documented in 37 patients (8 patients from endocrine to chemoendocrine therapy and 29 from chemoendocrine to endocrine treatment; p = 0.001, McNemar test). Treatment change was significant among patients ≤ 50 years (p = 0.002), luminal B tumors (p< 0.0001), stage II&IIIA disease (p < 0.0001) and node positive disease (p = 0.002). At a median follow-up of 12 months (3-75 months), one patient in the low risk group developed systemic relapse. Conclusions: Oncotype DX testing resulted in significant changes in the adjuvant treatment decisions in ER-positive, HER2-negative early breast cancer particularly in the case of young patients, Luminal B tumors, N1 disease and stage II-IIIA disease.