Individual and thin bundles of aminopolymer-functionalized single-walled carbon nanotubes (SWNTs) were successfully imaged using high-resolution transmission electron microscopy (HR-TEM). The corresponding electron energy loss spectroscopy (EELS) characterization of the same TEM specimen before and after ex situ thermal defunctionalization confirmed that the nanotube surface was covered with nitrogen-containing functionalities in the functionalized SWNT sample.