The relationships between electrification of energy supply, electricity intensity, and economic performance of the United States and 13 other members of the Organization of Economic Cooperation and Development (OECD) are reexamined to gain a better understanding of their historical development and likely future trends. The close agreement in the average and marginal electricity intensities of mature industrial economies with similar energy supply mixes suggests that in excess of I kWh, and possibly as much as 2 kWh, of additional electricity supply will be needed by the U.S. economy for every 1972 dollar of incremental GNP for the foreseeable future and that the share of primary energy consumption converted to electricity and the percentage of electricity in the energy supply mix will continue to rise. In addition, technical and institutional options to enhance the positive impact of electrification on economic growth and productivity are examined within the framework of a least-cost energy service strategy.