INTRODUCTIONIn most regional econometric models, regional manufacturing activity as measured by output, income, or employment is driven largely by national activity through an explicit demand-side, export-base framework. Although a demandoriented model may be useful for forecasting short-term fluctuations in manufacturing activity in slow-growing, highly industrialized regions of the North and East, it is less suited for forecasting long-term manufacturing growth in fast-growing, relatively underindustrialized regions of the South and West. In order to forecast long-term manufacturing growth in fast-growing regions, a supply-side approach is needed, in which the growth in regional manufacturing capacity is explicitly modeled.This paper reports on an attempt to implement a supply-side model of regional manufacturing growth for the state of Texas. The theoretical structure of the model follows the approach suggested by Engle (1974) and Crow (1979). Manufacturing investment is explicitly modeled and the growth in manufacturing capacity is the major determinant of the long-term growth in Texas manufacturing man-hours and output. The model is estimated on annual data for 15 industries over the period 1958-1978. The Texas manufacturing model has been embedded into an overall economic-demographic forecasting model for the state-the Texas Economic-Demographic Forecasting Model (TEDFM). The major use of TEDFM is to produce consistent, long-term forecasts of Texas economic and population growth.The organization of the remainder of this paper is as follows. Section 2 outlines the history of modeling manufacturing activity in regional econometric models and documents the need for a supply-side approach. Section 3 details the theoretical structure of the Texas manufacturing model, and Section 4 presents the results of the estimation of the investment, man-hours, and output equations. Results of an in-sample simulation of the manufacturing submodel (as part of TEDFM) are given in Section 5, and Section 6 summarizes the major results of this study and discusses their implications for future work on modeling regional manufacturing activity.