Objectives: We developed minimal incision-assisted retroperitoneoscopic surgery (MARP) in an attempt to pursue optimized patient-related benefits. We evaluated the clinical value of MARP for upper urinary tract diseases compared with pure retroperitoneoscopic surgery (PRPS). Patients and Methods: Between January 2003 and September 2008, PRPS and MARP were carried out in 338 and 85 patients, respectively. The upper urinary tract surgical procedures were defined as simple and complex procedures. We defined our experience from January 2003 to December 2005 as our early stage of PRPS learning curve. Our experience from January 2006 to September 2008 was defined as our late stage of PRPS learning curve. Patients' perioperative details were compared. Results: MARP was associated with shorter operative time for each complex procedure and with less frequent conversion to open surgery (2.4% vs. 11.3%, p - 0.023). A significantly greater proportion of MARP patients underwent complex procedures (81.2% vs. 49.1%, p < 0.001), and a significantly greater proportion of MARP were carried out at the early stage of PRPS learning curve (62.4% vs. 44.1%, p = 0.003). Estimated blood loss, hospital stay, the amount of analgesic use (diclofenac sodium suppository), and intraoperative and postoperative complications were comparable. Conclusions: MARP maintains the patient-related benefits of PRPS while allowing surgeons to perform more complex cases of upper urinary tract diseases and shortening the relevant operative time. It can be useful for cases in which the specimen is going to be extracted intact, when starting out learning retroperitoneoscopy, or when unable to progress the case using laparoscopic techniques.