Nanoparticles agglomerate and clump in solution, making it difficult to accurately deliver them for in vivo or in vitro experiments. Thus, experiments were conducted to determine the best method to suspend nanosized particles. Ultrafine and fine carbon black and titanium dioxide were suspended in phosphate buffered saline (PBS), rat and mouse bronchoalveolar lavage fluid (BALF), and PBS containing dipalmitoyl phosphatidylcholine (DPPC) and/or mouse serum albumin. To assess and compare how these various suspension media dispersed the nanoparticles, images were taken using light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results of this study show that PBS is not a satisfactory medium to prepare nanoparticle suspensions. However, BALF was an excellent media in which to suspend nanoparticles. The use of PBS containing protein or DPPC alone, in concentrations found in BALF, did not result in satisfactory particle dispersion. However, PBS-containing protein plus DPPC was satisfactory, although less effective than BALF.