This paper analyzes the geographical concentration of 32 manufacturing sectors over the 1972-1996 period for 13 European countries. Concentration has increased continuously over the sample period in employment terms, while remaining roughly unchanged in export terms. On average, increases in concentration were stronger prior to the launch of the Single Market than afterwards. The sectors most sensitive to the Single Market however, showed an acceleration in concentration after 1986. There is also evidence that low-tech industries are the most strongly concentrated, and that center-periphery gradients across countries are losing importance for industrial location in the EU.