Objective: To evaluate reliability and validity of a new tool for assessing the placement and promotional environment in grocery stores. Methods: Trained observers used the "GroPromo" instrument in 40 stores to code the placement of 7 products in 9 locations within a store, along with other promotional characteristics. To test construct validity, customers' receipts were coded for percentage of food purchases in each of the categories. Results: Of the 22 categories tested, 21 demonstrated moderate to high interrater reliability (intraclass correlation greater than or equal to = 0.61). When more unhealthy items were placed in prominent locations, a higher percentage of money was spent on less-healthy items, and a lower percentage of food dollars were spent on fruits and vegetables. The prominence of locations was more important than the number of locations. Conclusions and Implications: The "GroPromo" tool can be used to assess promotional practices in stores. Data may help advocates campaign for more healthy food items in key promotional locations. (Contains 4 tables and 1 figure.)