The effect of retail grocery market structure on the speed of adjustment of retail food prices to changes in producer prices, real wages, and the cost of energy was examined for SMSAs. Evidence failed to support the implication of the Mason-Bain paradigm that increased concentration reduces market efficiency as reflected in speed of retail price adjustment. Evidence of strong intertemporal relationships between change in producer prices and retail prices found for the categories meat, poultry, fish, eggs and cereal and baker products provide support to the hypothesis of cost-push inflation.