This paper discusses the many limitations of the official poverty lines applied in Sri Lanka (and many other nations). These include poverty lines’ reliance on expert-based determination of basic food and non-food needs, the fact that they are a monetary measure and so do not measure whether food or non-food needs were actually met, their reliance on (questionable) expert-based determination of thresholds, their inability to measure deprivation adequately in multiple dimensions (including housing and living conditions), and their focus on private consumption ignoring common resources which are important to well-being. Despite these limitations, poverty estimates are used by government as well as non-government agencies to guide national poverty-alleviation programmes and to strategise poverty-targeted interventions. It is likely that the household surveys used to set official poverty lines also fail to include the homeless, those living and sleeping in public places, streets, refugee camps and illegal dwellings. Further, the official definition of what constitutes an urban area (and its urban population) in Sri Lanka considerably under-states the actual urban population – and this too implies an under-estimation of the scale of urban poverty.