We report the synthesis of organized colloidal semiconductor nanocrystal / carbon singlewalled nanotube hybrid nanostructures. The synthetic protocol described here avoids the need for covalent chemical modification of carbon nanotube (CNT) surfaces. Specifically, InP quantum dots (QDs) and CdSe QDs were found to strongly adsorb onto the surfaces of carbon single-walled nanotubes (SWNTs) by gentle heating in organic solvents. Transmission electron microscopy (TEM) was used to characterize the semiconductor nanocrystal (NC) / SWNT assemblies, and revealed that the surfaces of the SWNT bundles template the adsorption of the NCs from solution. Small QDs were found to randomly absorb onto SWNTs, while larger QDs self-assembled into long linear chains. The nature of binding and ordering was investigated by simply considering van der Waals (vdW) forces for both NC-SWNT and NC-NC interactions. Quantum rods (QRs) were also found to adsorb along the nanotube surfaces. These findings have important implications for the synthesis of NC / SWNT hybrid nanostructures.