This work attempts to study the influence of a reactive compatibilizer on the uneven distribution of Fe(3)O(4) nanoparticles in polystyrene (PS)/polyamide 6 (PA6) blends and to present a novel, low-cost approach for fabricating PA6-based magnetic microspheres. By adding terminal maleic anhydride functionalized PS (FPS), we were able to observe significant reductions in both the PA6 domain size and its polydispersity index, as well as a redistribution of the Fe(3)O(4) from the PA6 domain into the PS matrix. Further experiments revealed that only when Fe(3)O(4) was added after a complete reaction of FPS with PA6 could the Fe(3)O(4) be preferentially dispersed into the PA6 domains. The influences of PA6 domain size, magnetic particle migration and competitive reaction of FPS on the nanoparticle dispersion were experimentally analyzed to elucidate the mechanism underlying the uneven distribution. (C) 2010 Elsevier Ltd. All rights reserved.