Single-walled carbon nanotube (SWNT) tips have been used to image nanostructures with high resolution. Studies of gold nanocrystal standards showed that SWNT tips provide a significant improvement in lateral resolution with respect to multi-walled nanotube tips and microfabricated Si tips. The nanotube tips were also used to resolve substructure within SWNTs deposited on surfaces. These results suggest that observed 1.5 nm high structures can correspond to several SWNTs aligned in parallel. In addition, SWNT tips exhibited superior resolution compared to conventional tips when imaging biological nanostructures, such as double-stranded DNA. The potential and future challenges of SWNT tips are discussed. © 1998 American Institute of Physics.