This study investigates the New Zealand health sector reforms from 1983 to 1997and examines whether the reform process has been consistent with the principles of the Treaty of Waitangi. It evaluates the impact of the reforms on Mäori from that perspective. The study introduces the health sector reforms generally and then their specific effects on Mäori. It draws on two research exercises undertaken by the author, being research for the Wai 692 Napier Hospital and Health Services claim to the Waitangi Tribunal and on improving Mäori Health outcomes for the National Health Committee. The methodologies used are those from the discipline of history. The study outlines the argument for Crown responsibilities under the Treaty and draws out the distinctions between Article 2 and Article 3 of the Treaty. It provides a historical background to the place of the Treaty in the health sector, and forms the basis for a Treaty based analysis of the health reforms and their impact. The New Zealand health sector has undergone massive government initiated structural change throughout the period under study. During this time the neo-liberal reforms have had a key role in reshaping health service structures. The process of change, the international influences on the changes, and the resulting entities are described. An example from Tainui Iwi of the effect of structural health reform illustrates the changes in Mäori health service provision by Mäori. Since 1983 successive governments have produced copious Mäori health policy. The key policy documents, and their recommendations, are identified, as is the degree to which they were implemented. The cyclical nature of such policy making suggests that it is not always followed by policy implementation. While Mäori are identified as a health gain priority, the evidence reviewed shows that the responsibility to implement and monitor the policy is diffuse and ineffective. The Wai 692 claim provides a detailed look at the impact of the 1990s health reform for Mäori. The claim was precipitated by the threatened closure of Napier Hospital, but was broadened to include a wide-ranging look at the impact of health reform on Mäori. As a case study it provides a specific example of one Iwi’s experience of the reality of policy implementation at that time versus policy making. Crown evaluation of the effectiveness of its own policies, and the extent to which its own agencies breach those policies is explored. The lack of control and accountability measures, plus the inability of the Crown to monitor (let alone sanction) success or failure, is highlighted. A contrast is drawn between the health and local government sectors, using the operation of the Resource Management Act (1991). The latest health sector reforms consequent on the 1999 Labour/Alliance coalition government are briefly considered, together with an overview of the Crown’s effectiveness in delivering improved Mäori health outcomes. The study suggests that the use of the Treaty as a cornerstone for Maori health policy formation and delivery may lead to more effective engagement between the Crown and Mäori in addressing Mäori health issues. The study concludes by asking the question, has the health sector reform process of the 1980s and 1990s itself been a Treaty breach? A brief postscript considers the further reform of the health sector beyond the period of study.