The holmium (Ho:YAG) laser can effectively fragment ureteral calculi of all compositions. It can also ablate tissue including neoplasms. Because the laser light can be carried through small flexible quartz fibers, it is ideally suited for use through small-diameter rigid and flexible ureteroscopes in the upper urinary tract. Although care must be used in application of the laser, the combination of fine control and limited tissue penetration allow it to be used safely in the ureter. Techniques for stone fragmentation, tumor ablation and stricture incision are described in detail.