Breast cancer is the most frequent cancer in women; in Egypt it affects 37.7% of all women and accounts for 29.1% of their cancer-related mortality. Cyclin D1 protein overexpression is found in up to 50% of breast cancers. The aim of this study is to study the correlations between cyclin D1 level and stages of breast cancer (TNM staging) and to study the correlations between cyclin D1 and routine markers used in breast cancer [cancer antigen 15-3 (CA15-3) and carcinoembryonic antigen (CEA)]. This study was performed on 80 female breast cancer patients. Ten healthy women served as controls. The patients were referred from the Assiut University Hospital and South Egypt Cancer Institute. None of the healthy women in the control group had elevated cyclin D1 level above the cutoff value. Elevated levels of cyclin D1 was detected in 80, 90, 95, and 100% of patients in groups II, III, IV, and V, respectively. There was a significant positive correlation between cyclin D1 positivity with CEA and CA15-3 concentrations. The combination of CA15-3, CEA, and cyclin D1 resulted in the highest sensitivity (95.2%), highest specificity (100%), and highest diagnostic accuracy (96%). The cyclin D1 level in samples obtained from Egyptian women with breast cancer is a good marker for the detection of breast cancer, and in the detection of metastasis as it correlates with the clinical staging of the disease. A combination of CA15-3, CEA, and cyclin D1 may be used as a panel for the diagnosis of metastasis among those patients.