Globally, breast cancer is the most common cancer in women worldwide, it represents about 25.0% of all cancer cases. In developing countries, breast cancer is mainly discovered at a late stage, which has a negative impact on the prognosis. To determine the extent of, and the factors contributing to, delay in breast cancer presentation, and to evaluate the mammography screening practice in breast cancer Libyan women. A descriptive cross-sectional study was carried out on five hundred and one breast cancer patients who attended the Oncology Outpatient Clinic of the Medical Department at Tripoli University Hospital and Tripoli Central Hospital during a period between February and August 2019, after the application of inclusion and exclusion criteria enrolled in the study. The mean age of the patients was 47.35±01.0 years, 55.1% of them were diagnosed in late stage (III and IV), and 30.9% of the patients were presented late (≥ 3 months). The time interval between the initial breast symptom and first presentation to a clinic ranged between 2^nd day and up to three years, with a median time of 1.5 months, and the main factor of the delayed presentation to a clinic was a lack of knowledge about symptoms (33.5%). The study revealed a significant association between delayed presentation and older age (P<0.001), low educational level (P<0.001), low family income (P<0.001), unemployed women (P< 0.002), postmenopausal women (P<0.001), patients with negative family history (P<0.05). This study concluded that the delayed presentation is found in less than a third of the study population, and lack of knowledge about breast cancer signs and symptoms is a common factor. Age, educational status, family income, unemployed women, menopausal status, and family history of breast cancer were all significant factors for delayed presentation. Improving women's awareness about breast cancer is needed and applying the policy of regular screening mammograms is a useful tool for early diagnosis and early treatment in Libya.