Mammogram grade 0 means the assessment is not completed, mostly due to the failure to perform ultrasound and other examinations at the same time for staff and equipment reasons or the patient’s unwillingness to wait for the entire examination to be completed. Breast BI-RADS classification refers to the assessment of the risk of malignancy of a lesion based on the results of ultrasound, mammography, and other imaging studies, and is divided into 0-6 categories, with category 0 meaning that the assessment has not been completed. Category 0 is generally described as “incomplete – requires further imaging” or “incomplete – requires comparison with previous mammogram”. Category 0 is generally used in screening and diagnostic mammography scenarios where the patient is unwilling or unable to wait for a complete exam, and the lack of ultrasound or special positional mammography such as spot compression or magnification makes it difficult to clarify the status of the lesion. Category 0 can also be used in situations where the mammogram is not negative or the lesion is not benign and comparison with previous mammograms is required for final evaluation. The use of Category 0 in this situation should ensure that a final evaluation can be made within 30 days and that changes and additions to the Category 0 results can be made. Patients are advised to communicate fully with their specialist for further investigation and treatment as prescribed.