Price incentives on healthy foods, price disincentives on unhealthy foods, and greater access to healthier foods have received much attention from policy-makers and researchers as potentially effective obesity policies. The aims of this study are to: 1) estimate models to quantify the own- and cross-price elasticities (i.e., sensitivity) of processed foods, fruits and vegetables, and fast-food demand by households with children; 2) develop new measures of healthy food access at the census tract level using GIS data on store locations and detailed scanner data on retailer-specific food sales, and evaluate the performance of the new measure in the context of the food demand model developed in Aim 1; and 3) expand the Research Triangle Institute (RTI) Food Pricing and Intake Simulator, an electronic toolkit for food pricing policy analyses developed by the study team with RWJF funding, to account for consumption of fruits and vegetables and fast foods and add new functional features to the toolkit. The updated toolkit will be able to simulate the dietary and fiscal impacts of food subsidies and taxes on overall nutrition and government revenue. This work will be conducted using data from children and adolescents ages 3 to 18 and their families who participated in Nielsen’s Homescan between 2004-2006, with a focus on lower-income and ethnic minorities.