Part I of this paper first presents information on trends and composition of social expenditure as in the OECD Social Expenditure database for the years 1980 – 2007. Over this period, public social expenditure as a percentage of GDP, on average across OECD, increased from 15.6% to 19.2%. Public pension spending (6.4% of GDP) and public health expenditure (5.8% of GDP) are the largest social spending items. Part I also presents social expenditure indicators that account for the effects of the tax system as well as indicators on private social expenditure.