Out-of-pocket health expenditures in Australia are high in international comparisons and have been growing at a faster rate than most other health costs in recent years. This raises concerns about the extent to which out-of-pocket costs have constrained access to health services for low income households. Using data from the ABS Household Expenditure Survey 2003–2004, we model the relationships between health expenditure shares and equivalised total expenditure for categories of out-of-pocket health expenditures and analyse the extent of protection given by concession cards. To allow for flexibility in the relationship we adopt Yatchew's semi-parametric estimation technique. This is the first detailed distributional analysis of household health expenditures in Australia. We find mixed evidence for the protection health concession cards give against high out-of-pocket health expenditures. Despite higher levels of subsidy, households with concession cards do not have lower out-of-pocket expenditures than non-cardholder households except for the highest expenditure quintile. Cards provide most protection for GP out-of-pocket expenditures.