OBJECTIVES: To perform an analysis of currently available manufacturer data regarding the character of ureteroscope damage. The high costs associated with the repair of flexible and semirigid ureteroscopes are well documented. Increased knowledge of the etiology of ureteroscope damage should aid urologists in prolonging the lives of these delicate instruments. METHODS: We requested data from the four major ureteroscope manufacturers (ACMI, Olympus America, Karl Storz, and Richard Wolf) on the types, speculated causes, costs, and frequency of ureteroscope damage. The results were tabulated in a blinded fashion and analyzed for trends. We then formulated guidelines that could be applied by practicing urologists. RESULTS: For both flexible and semirigid ureteroscopes, the frequency of repair increased with decreasing ureteroscope diameter and increasing instrument length. The cost of the repair was generally greater for flexible ureteroscopes (mean 4597 dollars) than for semirigid ureteroscopes (mean 2437 dollars). The major causes of flexible ureteroscope damage were working channel damage from laser burn or instrument passage and extreme scope deflection with an indwelling instrument. The primary reasons for semirigid ureteroscope repair included overtorquing and improper handling in the operating room and during sterile processing. CONCLUSIONS: Urologists can minimize the repair costs of flexible and semirigid ureteroscopes by taking precautions to eliminate laser fiber-induced damage and by avoiding overdeflection. Improved storage and handling of these instruments is also necessary. Although small-diameter ureteroscopes are favorable because of their increased mobility and ease of passage, physician and staff awareness of their increased fragility is vital in maximizing the longevity of these commonly used instruments.