Classify BI-RADS scores based on Mammograms not referring to other subclinical tests. Subjects and Methodology: The research method was a retrospective cohort study. Women, who were not diagnosed with breast cancer, had X-ray tests from April 2021 to March 2022. Four mammography images including both MLO and CC position views from each woman were used to diagnose following the Guidance of ACR BI-RADS 2013 by three oncological radiologists. Final BI-RADS scores based on mammograms were independently classified, although doctors could examine other testing results such as Ultrasound and/or other subclinical tests. Results: Total 2,351 women are enrolled in this study. Classification results of breast density type A, B, C, and D are 2.7%, 17.8%, 72.4%, and 7.1%, respectively. Similarly, rates of BI-RADS scores from BI-RADS 0 to BI-RADS 5 are 0.3%, 44%, 33.7%, 8.6%, 12.8%, and 0.6%, respectively. Conclusion: The most popular breast density type is C, and this result is known in many previous reports in Asian women. With respect to ACR BI-RADS 2013 guidance, type C and D are caused to reduce sensitivity of BI-RADS diagnosis using X-ray technique. Therefore, the rate of BI-RADS 4 score in this study should be carefully considered due to high rate of False positive using only Mammograms.