Background: Digital breast tomosynthesis (quasi three-dimensional [3D] mammography) is a relatively novel technique. It creates thin-slice reconstructions of the breast from low-dose digital mammographic images acquired at multiple angles. This evolution of mammography improves lesion visibility by reducing overlapping tissue. Hence, it has the potential to increase BC detection and to reduce false-positive (FP) findings. Objective: To review the role of 3D Digital Mammography in Studying of dense breast Lesions in adult female. Patients and methods: This was a retrospective study conducted on 40 patients who were eligible for examination by 3D Digital Mammography referred to WAFI center (women and fetal imaging center). The study was conducted during 12 months from January 2019 till January 2020 and was carried at Al-Azhar University Hospitals and WAFI Center (Woman and fetal imaging center). Results: There was no statistically significant difference between ultrasound (US) and tomosynthesis (TOMO) as regarding mass detection. There was a statistically significant increase as regarding calcification detection in TOMO than US. There was a statistically significant increase as regarding asymmetry detection in TOMO than US. There was no statistically significant difference between US & TOMO as regards Arch. Distortion detection. There was no statistically significant difference between US & TOMO as regards inflammatory reactions detection. There was statistically significant increase as regarding cyst detection in US than TOMO. There was a statistically significant increase as regarding dilated ducts detection in US than TOMO. There was a statistically significant increase as regarding added value detection in US than TOMO. There was no statistically significant difference between US & TOMO as regarding Breast Imaging-Reporting and Data System (BI-RADS). Conclusion: Both modalities were not similar in the ability to identify malignant lesions. Wide-angle digital breast tomosynthesis (DBT) was able to initially identify two more lesions <1cm in size; one more malignant focus in a patient with a multi-focal disease, and a small malignant lesion, a case with multiple benign lesions. Both lesions presented as small area of architectural distortion on DBT images (statistically, no significance despite the difference between the two modalities, p=0.07), also DBT has higher detection rate than US as regard calcification and focal asymmetry.