This thesis aims to explain the reasons for the severe deterioration experienced in the Brazilian tax system since the 1970s, and the inability of successive governments to enact comprehensive tax reform. Standard thinking on taxation in developing countries suggests that technical and administrative weaknesses lie at the heart of inadequate tax structures in developing countries, yet Brazil has shown a clear capacity for effective policy-making in other areas. Instead, it appears that deeper weaknesses at the level of political economy have conspired to result in a regressive and chaotic tax system, with the state unable to resist pressures from powerful social and political forces seeking to enhance their privileges or to block reform. After a review of the literature on taxation in developing countries in Chapter One, a political economy framework for the analysis of the policy process is advocated in Chapter Two, and against this background the thesis goes on to discuss the failure of successive attempts at tax reform in Brazil. Chapter Three examines the model of industrial development adopted by Brazil's military regime after 1964 and the role of tax policy in the period of rapid economic expansion that ensued. It asks why such an apparently successful growth strategy was to disintegrate so harshly, and argues that the political inability of the military regime to impose the costs of financing its programme on the richer groups upon which it depended for support was the key factor in provoking the descent into economic crisis. Chapter Four examines initial tax reform in the context of the democratic transition after 1985, culminating in the constitutional process of 1987-88. It shows that while some small advances were made with respect to objectives of revenue generation, equity and economic efficiency, a high degree of regime continuity ultimately determined that hopes for greater economic rationalisation and enhanced social equity through the tax system were left unanswered. Instead, conservative forces continued to thwart substantive progressive reform, while the resurgence of overwhelming regional pressures meant that concerns for efficiency and equity were almost completely ignored in the rush for increased revenue transfers from central government. Chapter Five examines the devastating impact which the 1988 constitution had upon federal finances and the consequences of this imbalance for economic stability in Brazil. It finds that the severe crisis in federal government solvency, provoked by the rigid revenue-decentralising provisions of the constitution, was to incapacitate the executive in its efforts to control hyperinflationary impulses. All attempts at comprehensive reform were thwarted by a combination of political circumstance and rejection from public- and private-sector groups. Governments were forced to resort to the same ad-hoc revenue-generating measures employed prior to the constitutional reform, with perverse consequences for economic efficiency and equity. Chapter Six deals with the issue of tax administration in Brazil, which has been almost completely neglected in favour of an overwhelming emphasis on structural reform. It examines the reasons for the rapid spread of tax evasion in Brazil and discusses the political obstacles which stand in the way of its effective combat. Chapter Seven analyses the failure of tax reform under the 'consensus' government of Fernando Henrique Cardoso, finding that despite Cardoso's vast electoral support and a growing consensus surrounding the need for profound economic reform, continued controversy over the content of proposals has seen tax reform shifted to the end of the list of government priorities. The sustainability of the current highly successful programme of economic stabilisation has come to depend upon the continued application of inefficient, ad-hoc measures aimed at maintaining the fiscal deficit under control. Chapter Eight applies the analytical framework developed in Chapter Two to the experience of tax policy in Brazil. Chapter Nine, finally, presents a conclusion to the thesis, with further suggestions for research. (Abstract shortened by ProQuest.).