Current technology has improved the modalities of intra-corporeal lithotripsy, including: ultrasound and ballistic, combined with different laser energies useful in the most important procedures for resolving urinary system stones. Nowadays, the amount of lasers and their availability has grown considerably, lasers like Holmium:Yttrium-Aluminum-Garnet (Ho:YAG) and Thulium Fiber Laser (TFL) are the most effective and safest alternatives for lithotripsy in several types of endo urological strategies for lithotripsy. The selection of appropriate laser energy is crucial to optimize the usefulness in the management of urinary tract stones and it depends on the clinical indications validated for the International Urolithiasis Alliance based in technology but also in principles of management from the reported outcomes based in the expertise of several endo urological surgeons. Both, Ho:YAG laser and TFL are effective systems of fragmentation in retrograde intrarenal surgery (RIRS) and percutaneous nephrolitotomy (PNL), even in the miniaturized percutaneous tracts enhanced with suction. Comparative with other types of lithotripsy, they have the same stone-free rates, low complication indexes, and optimal surgical operative times. Urologists must be familiar of with the properties of each laser to get the best surgical outcomes for the benefits of their patients. The present chapter will describe the clinical indications and the adequate use of laser fibers.