The use of a UHV nanoprobe allows for simultaneous electrical measurements of individual and bundles of carbon nanotubes while performing STM, SEM and Auger. The Four probe tips can be accurately positioned on to a one-dimensional nanostructure such as a nanotube to perform measurements of resistivity and electrical transport properties at low temperatures, while their exact position can be determined. Multi-walled carbon nanotubes (MWNTs) and single-walled carbon nanotubes (SWNTs) have been investigated. In particular, the effects of conductivity as a function of the presence or absence of a junction have been investigated. The effects of probe pressure and thermal annealing have been measured, as has the application of pressure to the nanotube. For MWNTs a resistance per unit distance of 4 kΩ/μm has been determined that matches theoretical models. Interestingly, resistance is independent of path at a MWCNT-MWCNT junction; however, there is a 100x increase in resistance at the point of the junction.