November 1996 The accumulation of knowledge affects trade performance and competitiveness, but trade also (through imports) affects the accumulation of knowledge. Padoan examines the properties of a dynamic disequilibrium model focused on trade specialization and the accumulation of knowledge. He uses a sector breakdown (four export and two import sectors) following Pavitt's (1984) taxonomy, which is especially appropriate for empirically analyzing the relationship between innovation activities and production and export performance. Steady-state analysis shows that: * Under perfectly balanced growth (no change in trade specialization and a uniform growth of knowledge), international diffusion of knowledge is irrelevant for growth. * Under unbalanced growth (with changes in the structure of specialization), the process of structural change may be enhanced by the effects on the domestic accumulation of knowledge of domestic spillover, as innovation activities in one sector generate positive externalities on the rest of the economy. The growth of foreign knowledge has an ambivalent effect on domestic performance because it is both a complement to, and a substitute for, domestic knowledge. Whenever these two effects do not perfectly match, the diffusion of international knowledge is associated with unbalanced growth. Imports of knowledge-intensive goods may not lead to higher growth unless there is sufficiently strong trade performance in the knowledge-intensive sectors (that is, there are thresholds in expansion of market share). This result, whose implications for developing countries is relevant, is not usually reported in the literature in which greater accumulation of foreign knowledge unambiguously leads to higher growth in the country that imports technology through trade. Unbalanced growth is also associated with output catching up. Technological catching up is necessary but not sufficient for balanced growth. Parameter estimates were obtained for France, Germany, Italy, Japan, and the United Kingdom. Results appear to be consistent with theoretical expectations about the importance of price and nonprice determinants of trade performance in the four sectors. Results also seem to be generally consistent with the distribution of revealed comparative advantages in the sense that the country cases exhibit high and significant price and knowledge elasticities and high adjustment speeds - suggesting a good capacity to deliver in sectors with revealed comparative advantage. Simulation exercises confirm steady-state results on the relevance of country differences in trade specialization and in the domestic accumulation of knowledge as they affect growth. They also clarify the relationship between growth and changes in the structure of trade specialization. This paper - a product of the International Trade Division, International Economics Department - is part of a larger effort in the department to assess the role of technology diffusion in economic development.