The morphology and structure of polycaproamide granules obtained by anionic polymerization of caprolactam in ethylbenzene in the presence of different activators (isocyanates) were investigated. The granules, which consist of a large number of initially separated small particles, were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and wide-angle X-ray scattering. On keeping all the synthesis parameters identical, correlations between the type of activator used, on the one side, and the high polymer content, chemical structure, agglomerates size, and fine morphology, on the other side, were found. The chemical structure of the components of the catalytic system seems to be the determining factor for the obtaining of some kinetically controlled morphologies. The results suggest that an adequate selection of the catalytic species is able to orient the process toward the obtention of materials with desired morphologies, in agreement with certain specific applications.