Introduction: In breast cancer, adjuvant endocrine therapy improves treatment outcomes. Though, not the whole patients completed their scheduled treatment protocols. This study aimed to assess adherence to oral hormonal therapy in Egyptian breast cancer patients. Patients and methods: From February 2022 to May 2022, a cross-sectional study was conducted at the National Cancer Institute, Breast Cancer Hospital. An interview was conducted, along with a survey to assess the adherence of breast cancer patients to oral hormonal treatment. Adherence was measured using the Morisky Medication Adherence Scale-8 (MMAS-8). Results: The survey was completed entirely by 300 patients. There were 98.3% females and 1.7 % males among the patients. 30% of the patients belonged to this age group (40-50 years). The majority of patients were postmenopausal (90.3%). 18% have a high level of education, while 53.3% are illiterates. 50.7% of patients have other chronic diseases. 44.7% prefer to get medication information from a physician, 27.7% prefer pharmacists, and 27.7% get medication information from both. 99.7% of patients received proper medication counselling. As a result of the MMAS-8 survey, 40.3% of all patients were high adherent to their oral hormonal treatment, 32.7% of the patients have moderate adherence, and 27% have low adherence. No subgroups (gender, age, educational level, duration of endocrine therapy, Breast cancer stage, or other co-morbidities) were significantly associated with adherence level. Conclusion: This study demonstrates significantly high and moderate adherence to oral endocrine therapy. Reasons for this could include proper medication counselling in the setting and regular patients’ follow-up.