In 90 patients treated with laser prostatectomy using the Urolase (n = 50) or Ultraline (n = 40) laser fiber, the fiber-tip durability was investigated. In general the Urolase fiber tips were less damaged than the Ultraline fiber tips. At visual inspection, 62% of the Urolase fiber tips were graded as minimally damaged in comparison with 28% of the Ultraline group. The Urolase fiber tips are more susceptible than the Ultraline fiber tips to damage caused by tissue contact, whereas the latter seem more fragile. Transmission measurements were performed in a laboratory setting to estimate the loss of energy output at the fiber tip due to damage. These measurements showed a major loss in almost all fibers. None of the Ultraline fibers had less than 10% transmission loss, and 18% of the Urolaser fibers had a transmission value of more than 90%. Finally, there seemed to be a poor correlation between the visual aspects of the fibers used and the changes in transmission.