Background: Breast cancer is a major health problem all over the world. Neutrophil-to-lymphocyte ratio (NLR) is an easy, cost-effective, readily available diagnostic tool for systemic inflammation. AIM: We aimed to evaluate whether baseline peripheral neutrophils to lymphocytes ratio in breast. cancer. patients is correlated with. pathological complete. response (pCR) following neoadjuvant. chemotherapy or not. Patients & Methods.:- This Observational prospective cohort study was. carried out in the Clinical Oncology Department. of Helwan University. Hospitals from October 2022 to September 2023. This study. involved 50 females with breast .cancer who. underwent treatment with neoadjuvant. chemotherapy protocol. Results: In this study, 17 patients (34%) achieved pCR following neoadjuvant chemotherapy with statistically significant higher. pCR rates among the group with lower NLR compared to the high NLR group. This study showed that12 (66.7%) patients in the lower NLR (≤1.69) achieved pCR while 5(15.6%) patients in the high NLR(≥1.69) achieved pCR (P value=0.002). Conclusion: Lower baseline peripheral NLR is associated with better, rates of pCR in, breast cancer patients receiving neoadjuvent chemotherapy which reflects better treatment outcomes