The variation in the impact of a brand's retail price promotion on its own sales (promotional price elasticity) and the sales of its competitors (promotional cross-price elasticities) during the period of the price promotion is studied. Brand characteristics and retailer policies significantly explain the variation in promotional price elasticities and cross-price elasticities across brands. Results are used to offer guidelines to retail managers for planning promotions in terms of what brands to promote, and how and when to promote them under three different retailer objectives: (1) to liquidate inventories; (2) to maximize product category sales; and (3) to maximize product category profits. These guidelines can be used by retailers in taking actions that will result in desirable levels of responses to price promotions of a brand—promotional price elasticity and promotional cross-price elasticities.