A set of purchasing power parities was constructed for the inputs and the outputs of the agricultural sector in 10 European countries and the United States. This made it possible to deflate both spatially and in time the nominal agricultural accounts. Real values of inputs and outputs made it possible to construct spatial indexes of productivity. These indexes measure the productivity gaps between countries for a given year. Extrapolation between 1973 and 1989 measures how these gaps have changed over time. The results show that the productivity of the United States has been 20 percent higher than the average productivity of European agriculture. This gap has persisted over time. However, large discrepancies exist in Europe and a few countries such as The Netherlands obtain a higher productivity than the United States.