Household expenditures on food are analyzed with the use of the 2006 Household Income and Expenditure Survey (HIES). A Bayesian penalized spline model, which is a semiparametric model, is estimated. The model allows a flexible relationship between household income and expenditures on food. Results suggest households with large family size, cars, own house, and employed, married and male household heads are more likely to consume more than others. There exit thresholds of food expenditure, and the relationship between income and food expenditure is not necessarily monotonic. Estimated average income elasticity of food expenditure is about 0.3.