OBJECTIVES: To determine the inequities in the household income depletion resulting from malaria treatment expenditures, the sacrifice of basic household needs (catastrophe) and the differences in payment strategies among different socio-economic and geographic groups in southeast Nigeria. METHODS: Data were gathered through pre-tested, structured questionnaires from a random sample of 2 250 householders in rural and urban parts of southeast Nigeria. The level of catastrophic malaria treatment expenditure was computed as the percentage of average monthly malaria treatment expenditure divided by the average monthly non-food household expenditure, using a threshold of 5%. Socio-economic inequity was established using a socio-economic status (SES) index, while a rural-urban comparison examined geographic disparities. RESULTS: The average cost to treat a case of malaria was 796.5 Naira ($6.64) for adults and 789.0 Naira ($6.58) for children. The monthly malaria treatment expenditure as a proportion of monthly household non-food expenditure was 7.8%, 8.5%, 5.5% and 3.9% for the most poor, very poor, poor and least poor SES groups respectively. Malaria treatment accounted for 7.1% and 5.0% of non-food expenditures for rural and urban dwellers, respectively. More than 95% of the people financed their treatment through out-of-pocket payment (OOP), with no SES and rural-urban variance, as opposed to insurance payment mechanisms and fee exemptions. CONCLUSION: There were socio-economic and geographic inequities in the financial burden resulting from malaria treatment. The treatment expenditure depleted more of the aggregate income of the two worse-off SES (Q1 and Q2) and of the rural dwellers. Government and donor agencies should institute the abolition of user fees for malaria, the transition from OOP to pre-payment mechanisms and the improvement of physical access to appropriate malaria treatment services, as well as subsidies and deferrals in order to engender financial risk protection from malaria treatment.