Australians' living arrangements have changed over the last several decades. Greater proportions of households contain only one person, a couple or a single-parent family. Such demographic trends have implications for poverty, which is identified at the household level. This paper explores the relationship between the depth of poverty and household type using longitudinal, unit-record data. Lone persons and single parents are the poorest. Poverty increases significantly at the beginning of a spell of living alone regardless of previous living arrangements but especially for people leaving the household of their parent(s). Except for the elderly, poverty decreases significantly at the end of a spell of living alone regardless of the subsequent household type. Notably, poverty decreases when people living alone become single parents and single parents who begin living alone experience an increase in poverty. The explanation lies with accompanying changes in government non-income support payments, imputed rent on owner-occupied, public and rent-free housing, and the number of nondependent people in single parents' households.