This final rule revises interim final regulations on Medicare coverage of screening mammography that were published in the Federal Register on December 31, 1990 (55 FR 53510). Those regulations implemented section 4163 of the Omnibus Budget Reconciliation Act of 1990, setting forth payment limitations and conditions for coverage of screening mammography. The conditions consist of quality standards to ensure the safety and accuracy of screening mammography services performed by qualified physicians and other suppliers of these services. As a result of the implementation of the Mammography Quality Standards Act of 1992 (MQSA) by the Food and Drug Administration (FDA), we are conforming the conditions for coverage to the applicable FDA certification requirements that all Medicare suppliers of services must meet effective October 1, 1994. The revisions in this final rule also respond to certain comments we received on the interim final rule published on December 31, 1990; they provide clarification of certain of its provisions; and they establish conditions for coverage of diagnostic mammography that are similar to those we have established for screening mammography. In addition, this final rule reflects changes resulting from the final rule on the fee schedule for physicians' services, which was published in the Federal Register on December 2, 1993 (58 FR 63626).