A theoretical investigation was made of the scanning tunneling microscopic images and conductance signatures of defective carbon nanotubes. The defects considered were those that formed on nanotubes under tension, both in the absence and presence of additional carbon atoms. The most prominent features observed in the scanning tunneling microscopy images were a set of bright rings whose positions correlated with the location of pentagons within the defect. These features were useful as they enabled the easy identification of many of the defects. In contrast, most of the defects had only a relatively modest effect upon the transport properties of the nanotubes. While there was a general decrease in the conductance of the nanotube due to scattering effects, there appeared to be no unique feature that could be associated with any of the defects investigated. This precluded the use of transport measurements as a means of defect identification. The scanning tunneling microscopy images and conductances of nanotube heterojunctions, as well as tubes under various bias voltages, were also explored. Theoretical STM Signatures and Transport Properties of Native Defects in Carbon Nanotubes. D.Orlikowski, M.B.Nardelli, J.Bernholc, C.Roland: Physical Review B, 2000, 61[20], 14194-203