The paper presents a significant revision of the World Bank's estimates of global poverty, incorporating new and improved data. It finds that extreme poverty, defined by the standards of the world's poorest countries, is more widespread than previously thought. However, the data also show a consistent decline in poverty incidence and depth since the early 1980s. For 2005, the estimate is that 1.4 billion people, or one-quarter of the developing world's population, lived below the international poverty line of $1.25 per day. This is a decrease from 1.9 billion people, or half the population, in 1981. The poverty rate in East Asia fell from nearly 80% to under 20%, while it remained around 50% in Sub-Saharan Africa, though with signs of progress since the mid-1990s. The paper uses three main data sources: the 2005 International Comparison Program (ICP), a new compilation of poverty lines for developing countries, and a large number of household surveys. The ICP provides more rigorous standards for defining internationally comparable commodities, leading to revised purchasing power parity (PPP) estimates. The new poverty lines are based on national poverty lines from the World Bank's country-specific Poverty Assessments and Poverty Reduction Strategy Papers. The paper also discusses the robustness of the results to different poverty lines and the impact of survey data on poverty measures. Overall, the findings suggest that while the developing world is poorer than previously estimated, the progress against poverty remains significant.The paper presents a significant revision of the World Bank's estimates of global poverty, incorporating new and improved data. It finds that extreme poverty, defined by the standards of the world's poorest countries, is more widespread than previously thought. However, the data also show a consistent decline in poverty incidence and depth since the early 1980s. For 2005, the estimate is that 1.4 billion people, or one-quarter of the developing world's population, lived below the international poverty line of $1.25 per day. This is a decrease from 1.9 billion people, or half the population, in 1981. The poverty rate in East Asia fell from nearly 80% to under 20%, while it remained around 50% in Sub-Saharan Africa, though with signs of progress since the mid-1990s. The paper uses three main data sources: the 2005 International Comparison Program (ICP), a new compilation of poverty lines for developing countries, and a large number of household surveys. The ICP provides more rigorous standards for defining internationally comparable commodities, leading to revised purchasing power parity (PPP) estimates. The new poverty lines are based on national poverty lines from the World Bank's country-specific Poverty Assessments and Poverty Reduction Strategy Papers. The paper also discusses the robustness of the results to different poverty lines and the impact of survey data on poverty measures. Overall, the findings suggest that while the developing world is poorer than previously estimated, the progress against poverty remains significant.