This study evaluates the promotion and advertising impacts on the demand for scanned purchases of Vidalia onions and estimates returns to promotion expenditures. The analysis uses supermarket scanner data collected from scanned purchases of Vidalia onions and promotion expenditures generated by the Vidalia Onion Marketing Order. An error-components model is estimated to determine the impacts of promotion expenditures for scanned purchases of Vidalia onions, own price, prices of substitutes and complements, demographics, and seasonal variables for 10 different markets over a 260-week period from 1996 to 2001.