As in many states around the country, health care costs in Massachusetts had risen to an unprecedented proportion of the state budget by the early 1980s. State health policymakers realized that dramatic changes were needed in the political process to break provider control over health policy decisions. This paper presents a case study of policy change in Massachusetts between 1982 and 1988. State officials formulated a strategy to mobilize corporate interests, which were already awakening to the problems of high health care costs, as a countervailing power to the political monopoly of provider interests. Once mobilized, business interests became organized politically and even became dominant at times, controlling both the policy agenda and its process. Ultimately, business came to be viewed as a permanent part of the coalitions and commissions that helped formulate state health policy. Although initially allied with provider interests, business eventually forged a stronger alliance with the state, an alliance that has the potential to force structural change in health care politics in Massachusetts for years to come. The paper raises questions about the consequences of such alliances between public and private power for both the content and the process of health policymaking at the state level.