Background: Breast cancer can be diagnosed using imaging modalities and histopathology. The description of the mass shape found via mammography needs to be confirmed by an anatomical pathology examination. Therefore, research regarding the comparison of mass shape based on BI-RADS mammography classification with histopathological grading of breast cancer patients is important. Objective: Analyzing the differences in mass shape based on the BI-RADS mammography classification between histopathological grading of breast cancer patients at Dr. Soetomo General Hospital Surabaya. Method: This type of research is an analytical observational study with a comparative approach using patient medical records in the form of age data, mammography examinations of breast cancer patients who were diagnosed based on histopathology results at Dr. Soetomo General Hospital Surabaya during the period January 2017 to December 2021. Results: Total breast cancer samples at Dr. Soetemo General Hospital Surabaya for the period January 2017 to December 2021 is 229 data. Breast cancer patients are dominated by the age group 40 – 49 years (37.6%), the majority of masses are found in the right breast (54.1%), the shape of the mass is predominantly irregular (86.5%), the most histopathological grading is in grade 3 (53.3%), and the comparison of mass shape between histopathological grading had a value of p = 0.137 (p > 0.05). Conclusion: Breast cancer patients at Dr. Soetomo General Hospital Surabaya for the period January 2017 to December 2021 is dominated by the 40 – 49 year age group. Most of the masses were in the right breast. The most common mass shape found was irregular and the most frequent histopathological grading was grade 3. There were no differences in mass shape between histopathological gradings.