There is disagreement about who is to be the primary payer when dual coverage exists under Medicare and a employer-sponsored group health plan for federal, state, and local government employees after the Omnibus Budget Reconciliation Act of 1986. Medicare administrators of the Health Care Financing Administration interpret the Act as applying to government-sponsored plans; administrators of federal, state, and local government-sponsored plans do not. This report discusses the background of the disagreement and delays beneficiaries could experience getting their bills paid. The report concludes that the Social Security Act should be amended to resolve differences in interpretation by stating that Medicare is the second payer to government plans under section 1862(b)(4) of the Act to the same extent that the section applies to other health plans. Quick action is recommended to avoid delays in paying disabled beneficiary claims. (ABL)