This paper reviews and assesses how urban poverty in Zambia is defined and measured by the government, using data from the Jesuit Centre for Theological Reflection (JCTR). It shows the often dramatic differences in the scale and nature of urban poverty, depending on what poverty measurements are chosen and applied. Applying the government poverty line, which takes no account of differences in costs between rural and urban areas, shows the incidence of urban poverty falling from 49 per cent in 1991 to 27.5 per cent in 2010; but a food basket based on what urban households eat is twice the cost of the food basket used in the official poverty line. In addition, as the paper describes, what urban poor households pay for food is often particularly high as they cannot buy in bulk. The official poverty line’s allowance for housing costs is based on what low-income groups spend on housing, not on the costs of the cheapest reasonable quality accommodation. The JCTR estimate for the cost of essential non-food needs is twice that in the official poverty line, and the JCTR review of house prices shows that the cost of “adequate” housing in cities is far higher than the allowance for housing in poverty lines. The paper also discusses other reasons why official poverty lines understate urban poverty, including neglecting the costs low-income groups face for transport, health care and keeping their children in school.