Carbon nanohorns (CNHs) are a new type of single-walled carbon nanotubes (SWNTs). They are composed of tubes with a diameter between 2 to 5nm aggregated in a spherical form that resembles that of a sea urchin or a dahlia. Endowed with this unique morphology, functionalized CNHs ( f-CNHs)are currently under careful scrutiny as novel drug containers for a controlled and timed delivery. A prerequisite for biomedical applications is the solubility of such material. The problem of CNH solubility has been partially solved as a certain number of organic reactions can be applied to functionalize them, which makes their manipulation easier and improves their biocompatibility. f-CNHs have been proposed for controlled drug release of anti-inﬂammatory and anticancer agents including dexamethasone, cis-platin, and doxorubicin. Alternatively, CNHs have been modiﬁed with magnetite and administered in vivo for magnetic resonance imaging (MRI) applications. These studies have been complemented by the assessment of a reduced toxicity displayed by the functionalized horns. Indeed, Isobe et al. have shown that f-CNHs are rapidly internalized into ﬁbroblastic cell lines without affecting the cell viability in comparison to other inorganic nanoparticles such as quartz and TiO2.