Background In the absence of functional social security mechanisms for elderly people in Nigeria, elderly households are solely responsible for geriatric healthcare costs, which can lead to catastrophic health expenditures (CHE) – particularly among the poor. This study investigates the key determinants of CHE among poorly insured elderly households in Nigeria. We also offer some policy options for reducing the risk of CHE. Methods Data on out-of pocket payments and self-reported health status were sourced from the Nigerian General Household Panel Survey (NGHPS) in Nigeria, conducted by the National Bureau of Statistics in 2010, with technical support from the World Bank. CHE was defined at the 10 % of total consumption expenditure threshold. The determinants of CHE and their marginal effects were investigated using probit regressions. An elderly household is defined as a household with at least one elderly member ≥ 50 years old. Results The proportion of elderly households with CHE is 9.6 %. Poorer and smaller elderly households were most at risk of CHE. Female-headed households were less likely to incur CHE compared to male-headed households (p < 0.01). Conversely, households with informal health financing arrangements were less likely to incur CHE (p < 0.001). Education and utilising a health promoting tool, such as treated bednets increased the probability of incurring CHE in Urban Nigeria. Conclusion Findings from this paper should prompt policy action to financially support poor elderly households at risk of CHE in Urban Nigeria. The Nigerian government should enhance the national health insurance scheme to provide better coverage for elderly people, thereby protecting elderly households from incurring CHE.