This study examined novel types of drug carriers based on polyelectrolyte complexes with water-soluble chitosan (WSC) and all-trans retinoic acid (atRA). Nanoparticulate polyelectrolyte complexes between chitosan and drug were successively formed through ultrasonication and particle size was ranged about 50 - 800 nm. Morphology of chitosan polyion complex nanoparticles observed with transmission electron microscope (TEM) was spherical shapes. Loading efficiency of drug into chitosan polyelectrolyte complexes was over 40 % (w/w). This drug loading efficiency was higher than other types of drug carriers such as liposomes, conventional nanoparticles, and lipid nanoparticles.