The Physicians for a National Health Program proposes to cover all Americans under a single, comprehensive public insurance program without copayments or deductibles and with free choice of provider. Such a national health program could reap tens of billions dollars in administrative savings in the initial years, enough to fund generous increases in health care services not only for the uninsured, but for the underinsured as well. We delineate a transitional national health program budget that would hold overall health spending at current levels while accommodating increases in hospital and physician utilization. Future national health program spending would be indexed to the growth in gross national product adjusted for demographic, epidemiologic, and technologic shifts. Financing for the national health program would transfer funds into the public program without disrupting the general pattern of current revenue sources. We suggest a funding package that would augment existing government health spending with earmarked health care taxes. Because these new taxes would replace employer-employee insurance premiums and substantial portions of current out-of-pocket expenditures, they would not increase health costs for the average American.