Single-walled carbon nanotubes (SWNTs), a member of the carbon family, are the one-dimensional analogues of zero-dimensional fullerene molecules with unique structural and electronic properties. Since the discovery of SWNTs, they have been extensively studied for biomedical applications. In biological media SWNTs have unique near-infrared intrinsic fluorescence, inherent Raman spectroscopy and photoacoustic signal associated with the graphene in SWNTs which makes them ideal for noninvasive and high sensitivity detection. SWNTs have been broadly investigated as imaging agents for the evaluation of tumor targeting and localization of SWNTs in vitro and in vivo. Rational functionalization can also endow SWNTs with desired properties for biomedical applications. Functionalized SWNTs with significantly reduced toxicity have been employed as carriers to deliver various anticancer drugs, proteins and nucleic acids to the diseased tissues specifically and maximize the bioavailability of the drugs by improving solubility and increasing circulation time. This manuscript will highlight the recent employment of SWNTs in the field of nanomedicine and bioimaging, and also outline the challenges and future opportunities for biomedical applications of SWNTs.