Main text A first key comparison has been made between the air-kerma standards of the KRISS, Republic of Korea, and the BIPM in mammography x-ray beams. The results show the standards to be in agreement at the level of the expanded uncertainty for the comparison of 4.4 parts in 103. The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).