This Report provides unique information for each of the thirty four OECD countries on the income taxes paid by workers, their social security contributions, the family benefits they receive in the form of cash transfers as well as the social security contributions and payroll taxes paid by their employers. Results reported include the marginal and average tax burden for one- and two-earner households, and the implied total labour costs for employers. These data are widely used in academic research and in the formulation and evaluation of social and economic policies. The taxpayer specific detail in this Report enables it to complement the information provided annually in the Revenue Statistics, a publication providing internationally comparative data on tax levels and tax structures in OECD countries. The methodology followed in this Report is described briefly in the introduction section below and in more detail in the Annex. The tables and charts present estimates of tax burdens and of the tax “wedge” between labour costs and net take-home pay for eight illustrative family types on comparable levels of income. The key results for 2013 are summarised in Section 2 below. Part I of the Report presents more detailed results for 2013, together with definitive results for 2012 and discusses the changes between the two years. Part II of the Report reviews historical changes in tax burdens between 2000 and 2013.