Objective: The proper time to commence adjuvant chemotherapy after primary surgery for breast cancer is unknown. It is usually prescribed within 2-3 months after definitive surgery. The aim of this retrospective study was to assess the impact of adjuvant chemotherapy (CT) delay beyond 3 weeks ( 21 days) in premenopausal patients with ER-absent tumors being treated for early stages breast cancer on overall survival (OS) and disease-free survival (DFS). Methods: This retrospective study was conducted through revision of medical records of premenopausal patients diagnosed with early stage Ⅰ-ⅢA breast cancer and ER-absent tumors who received adjuvant CT after definitive surgery at the Department of Clinical Oncology, Ain-Shams University Hospitals. Results: Between 2005 and 2008, 105 patients were retrospectively analyzed and included. Patients were divided into 2 groups: Group A including 48 patients who started adjuvant CT<21 days of surgery and group B which included 57 patients who had CT delay ≥ 21 days. Both groups were matched demographically. Comparisons of overall survival, and disease-free survival between group A and group B patients all favored group A. At 5-year the OS rates were 87% and 73% for groups A and B respectively (P=0.001), while DFS rates were 85% and 64% in groups A and B respectively (P=0.001). Analysis of other prognostic factors (age, T, N, grade, HER2 status, surgery type, CT type, local radiotherapy received) were analyzed. Only nodal status predicted for worse DFS (P=0.05) and OS (P=0.006). Conclusion: Delay in initiating adjuvant chemotherapy for early stage breast cancer patients with ER-absent tumors was associated with a decrease in both OS and DFS rates. The aim of this retrospective study was to assess the impact of adjuvant chemotherapy (CT) delay beyond 3 weeks (21 days) in premenopausal patients with ER-absent tumors being treated for early stages of breast cancer on overall survival (OS) and disease-free survival (DFS). Methods: This retrospective study was conducted through revision of medical records of premenopausal Patients diagnosed with early stage I-III A breast cancer and ER-absent tumors who received adjuvant CT after definitive surgery at the Department of Clinical Oncology, Ain-Shams University Hospitals. Results: Between 2005 and 2008, 105 patients were retrospectively analyzed and included. Patients were divided into 2 groups: Group A including 48 patients who started adjuvant CT <21 days of surgery and group B which included 57 patients who had CT delay ≥ 21 days. Both groups were matched demographically. Comparisons of overall survival, and disease-free survival between group A and group B patients all favored group A. At 5-year the OS rates were 87% and 73% for groups A and B respectively (P = 0.001), while DFS rates were 85% and 64% in groups A and B respectively (P = 0.001). Analysis of other prognostic factors (age, T, N, grade, HER2 status, Only nodal status predicted for worse DFS (P = 0.05) and OS (P = 0.006). Conclusion: Delay in initiating adjuvant chemotherapy for early stage breast cancer patients with ER-absent tumors was associated with a decrease in both OS and DFS rates.