An error correction model was fitted to monthly data on net retail gasoline prices for the U.K. and the U.S.A. over the period January 1980-June 1996 in order to examine the short-run response of gasoline prices to changes in crude oil costs and exchange rate. The hypothesis of a symmetric response by gasoline station owners to crude oil price rises and falls was rejected by the data for both the U.K. and the U.S.A. A similar hypothesis in regard to the exchange rate was also rejected by the data.