Carboxymethylchitosan/poly(amidoamine) (CMCht/PAMAM) dendrimer nanoparticles, comprised of a PAMAM dendrimer core grafted with chains of CMCht, have recently been proposed for intracellular drug delivery. In previous reports, these nanoparticles had lower levels of cytotoxicity when compared with traditional dendrimers. In this study, the short-term in vivo biodistribution of fluorescein isothiocyanate (FITC)-labeled CMCht/PAMAM dendrimer nanoparticles after intravenous (IV) injections in Wistar Han rats was determined. The brain, liver, kidney, and lung were collected at 24, 48, and 72 h after injection and stained with phalloidin–tetramethylrhodamine isothiocyanate (TRITC, red) and 4