Because of their small size, robust structure and unique characteristics, carbon nanotubes (CNTs) are increasingly being used in a variety of biomedical applications, materials and products. As their use increases, so does the probability of their unintended release and human exposure. Therefore, it is important to establish their potential biodistribution and biopersistence to better understand the potential effects of their exposure to humans. This study examines the distribution of CNTs in CD-1 mice after exposure by inhalation of single-walled carbon nanotubes (SWCNTs) and investigates the possibility that inhaled nanoparticles could enter the circulatory system via the lungs. Raman spectroscopy was employed for the detection of CNTs in lung tissue and blood based on their unique spectroscopic signatures. These studies have important implications concerning the potential effects of exposure to SWCNTs and their use as potential transport vehicles in nanomedicine. Copyright © 2012 John Wiley & Sons, Ltd.