The Theory of Clusters, which origins are rooted on marshallian theory of industrial districts, have gained a new thrust with Porter´s recent works. In his theory, elements of Economic Geography, Industrial Complexes, and competitive dynamics are meshed together into the porterian cluster characterization. Nevertheless, the cluster construct is still in need of further formalization in order to be fully operational. On the same token, critics to Porter question whether the concept of cluster is applicable to developing countries. The intention of this article is to open some new avenues of investigation that could advance the issues mentioned. Based on São José dos Campos example, we mapped the region´s aircraft and armament clusters, by using the specialization index (IE). In the sequence, we established the relationship between the cluster existence and the region´s quality of life (represented by the IDH-M index). Finally, we pointed out the possibilities of expansion of the porterian theory of clusters, based on the analysis presented and previous investigation on the region.