Since the early 1970s, the issue of poverty measurement has generated a considerable literature in South East Asia, as in other parts of the developing world. The most frequently used measurement has been the well-known ‘headcount’ method 1 although some studies have also used other indicators. An appropriate poverty line is estimated, and then applied to data derived from household income or expenditure surveys, in order to determine the proportion of the population, or of households, whose income or expenditure falls below the poverty threshold. In Indonesia, Malaysia, Thailand, Singapore and the Philippines, a number of different poverty estimates have been made by different agencies and individuals using this ‘headcount’ method. Recently it has also been used in Vietnam. However there has been little uniformity in the choice of poverty line, even between different studies on a single country, let alone between different countries. 2 It is thus difficult to make any crosscountry comparison on the extent of poverty in South East Asia, and indeed few such comparisons have been attempted. While it seems quite obvious from even a cursory inspection of the studies for individual countries that the poverty lines used are not comparable, it is far from clear how a common poverty line should be constructed. In the second part of this chapter, I attempt a comparison of the extent of poverty between countries and regions in South East Asia. But first, it will be useful to examine the data base available for the study of poverty in South East Asia, and briefly survey the results from some of the more important studies.