A methodology for estimating a demand system from household survey data is developed and applied to the 1987-88 Nationwide Food Consumption Survey data. The empirical results are sets of estimated demand elasticities for households segmented with different income levels. In addition, we apply these demand elasticities to estimate the implied nutrient elasticities for low-income households. The estimation results are useful in evaluating some food policy and program effects related to households of a specific income level.