The study is directed toward developing a worldwide simulation model of aluminum and copper that describes the interaction between the two markets. The model provides a tool for base market forecasting and for analyzing the implications of alternative market conditions. The model specification is dynamic and based on both economic theory and the understanding of the operation of the copper and aluminum markets. The demand side began with an examination of the utility theory and it deals exhaustively with substitutability and consumer choice. For each metal, demand is disaggregated regionally and, within the United States, on a consuming industry basis. The regional demand for each metal equation is specified for total United States, Europe, Japan, and total free world.