The study describes the evolution, since the Portuguese accession to the European Community, in 1986, of the different types of farm holdings (household-farms, corporations, co-operatives and other legal forms), using the Agricultural Census data. In addition, the experience of agricultural taxation in Portugal in the context of the ongoing policy debate about the tax structure and tax reform affecting agricultural producers is addressed for different categories of farms. The research also examines the problems associated with tax regimes. A major problem has been the measurement of the actual taxable farm income. The different measures to estimate farm income are explained for the various taxation regimes.