The Registry Partners May 2020 CTR Coding Break reviews the 2018 SEER Coding and Staging Manual Appendix C for site-specific coding modules. Appendix C provides site-specific instructions to help abstract a case efficiently and accurately. Some modules include site-specific coding guidelines for coding primary site including priority order, the extent of disease, solid tumor rules, and surgery codes. The presentation focuses on the breast and bladder sites. The priority order for coding subsites of the breast when there is conflicting information includes #1, the operative report, #2, the pathology report, #3, mammogram/ultrasound, and finally the physical exam. The breast coding guidelines in relation to the o’clock position and quadrants are reviewed. Breast subsite examples are provided and discussed. The priority order for coding subsites of the bladder when there is conflicting information includes #1, the operative report (TURB), and #2, the pathology report. Bladder site examples are also provided and discussed.