OBJECTIVE To present a unique completely standardized sequence of steps performed before, during, and after flexible ureteroscopy (FURS) that achieves superior results for FURS treatment of renal calculi. MATERIALS AND METHODS The "Freiburg FURS technique" includes the following steps: (a) preoperative ureteral stenting; (b) placement of 2 hydrophilic wires; (c) semirigid ureteroscopy before FURS; (d) the use of a large access sheath (14F-16F) if multiple ureteral passages are expected; (e) the use of a 2-working channel flexible endoscope; (f) a modified active flushing system; and (g) an advanced holmium laser technique with complete stone extraction. We performed a prospective analysis of 153 consecutive FURS procedures for nephrolithiasis from August 2009 to July 2011. RESULTS Data analysis revealed an "immediate" stone-free rate of 96.7% (as confirmed by endoscopy, fluoroscopy, and ultrasonography), a medium of 2.3 stones, and a cumulative stone size of 10.5 mm (range 3-43). The operative time was 67 minutes (range 20-160). The use of an access sheath was required in 71% of the patients and the postoperative use of a double-J stent in 57% of patients. Complications (Clavien grade II and III) developed in 9.1% of patients (including 7 with minimal perforation that required ureteral stenting for 1 month, 3 with secondary flank pain/hydronephrosis requiring double-J stenting and hospitalization, and 4 with fever or urinary tract infections requiring antibiotic therapy. Follow-up examinations after 3 months showed no late complications. CONCLUSION The modified FURS technique provided clinically superior results with a low complication rate. However, the approach requires the use of considerable resources, both technical and surgical and financial. UROLOGY 80: 1198-1202, 2012. (C) 2012 Elsevier Inc.