This paper presents a new Multidimensional Poverty Index (MPI) for 104 developing countries. It is the first time multidimensional poverty is estimated using micro datasets (household surveys) for such a large number of countries which cover about 78 percent of the world´s population. The MPI has the mathematical structure of one of the Alkire and Foster poverty multidimensional measures and it is composed of ten indicators corresponding to same three dimensions as the Human Development Index: Education, Health and Standard of Living. Our results indicate that 1,700 million people in the world live in acute poverty, a figure that is between the $1.25/day and $2/day poverty rates. Yet it is no $1.5/day measure. The MPI captures direct failures in functionings that Amartya Sen argues should form the focal space for describing and reducing poverty. It constitutes a tool with an extraordinary potential to target the poorest, track the Millennium Development Goals, and design policies that directly address the interlocking deprivations poor people experience. This paper presents the methodology and components in the MPI, describes main results, and shares basic robustness tests.