The objectives of this study were to evaluate purchase flows of agricultural raw materials and to establish the commercial boundaries of the city of Temuco in the IX Region of Chile in 2002-2003. Local Planning Boards were polled from the districts of the IX Region and in the provinces of Arauco, Biobio and Valdivia were also included. The gravitational determinist model on demarcation of commercial areas was used. According to the results obtained, the city of Temuco, as leader city, attracts expense flow from all of the neighbouring districts in the IX Region and also from border districts in the VIII and X Regions, totalizing 35 districts, north and south of Temuco. There were shared zones of attraction with Valdivia, Concepcion and Los Angeles. The coefficients of the population variables and number of commercial patents used to measure the commercial attraction of the districts of origin on the expense flows were negative. The coefficients for population, number of commercial patents and sales area of the districts of destination of flows were positive, whereas both restriction variables had negative coefficients. The coefficients of the three variables were statistically significant (p<0.05) in the specification of the gravitational model that uses population as an attribute of the district of origin, destination of the commercial flows and travel time as restriction variables. The global adjustment of the model improved when other variables that reflected the commercial attraction of the procurement centers were introduced, i.e. number of business patents of agricultural supply stores and the related commercial area, showing determination coefficients higher than 40%, considered acceptable in this type of research. Not withstanding, the variable referred to the district of origin of the expense re-routing had statistically non-significant coefficients (p>0.05) and were positive for the commercial area. Therefore, It was determined that movement of raw material acquisitions outside the district where farms were located is done in the interurban commercial centres, that offered the largest variety of products, and the best business conditions and services to farmers. Para evaluar la existencia de flujos de compra de insumos agrícolas atraídos por Temuco y delimitar su área comercial, se encuestó a los Secretarios Comunales de Planificación de las comunas de la IX Región y de las provincias de Arauco, Biobío y Valdivia, definidas como unidades de estudio por el modelo gravitacional determinista de delimitación de áreas comerciales. Temuco, como cabecera comercial del área, atrajo flujos de gasto de todas las comunas de la IX Región y de comunas limítrofes de la VIII y X Región de Chile, totalizando 35 comunas atraídas comercialmente. Se observaron zonas de gravitación compartida con las áreas comerciales de las ciudades de Valdivia, Concepción y Los Angeles. Mediante la estimación del modelo de gravitación comercial tradicional, se determinó que los desplazamientos de compra fuera de la comuna de ubicación del predio para las adquisiciones de insumos agrícolas, se realizaron seleccionando los centros de compra interurbanos de mayor oferta comercial, que ofrecen mejores condiciones comerciales y de servicios a los productores agrícolas, actuando la distancia o el tiempo de desplazamiento como factores de restricción a los desplazamientos de compra.