Abstract: Objective: To investigate the clinical effects of minimally invasive percutaneous nephroscopy by holmium laser for endo-incision and drainage of deep kidney cysts. Method:From Feb. 2009 to Dec. 2012, 30 cases were treated with minimally invasive percutaneous nephroscopy by holmium laser for endo-incision and drainage of deep kidney cysts, including 19 males and 11 females. The average age of the patients was 47 (range, 36-58) years old. The average diameter of cysts was 6.0 (range, 5.0-7.0) cm. All cysts with thick walls were closed to the renal collecting system. Twelve cases guided and monitored by B ultrasound were inserted via kidney calices, which were adjoined the cysts, to the renal pelvis. Then, we inserted ureteroscope, cauterizing and opening pelvis and cysts by holmium laser. Percutaneous ureteroscopes were used in 18 cases. We then cauterized and opened cysts to pelvis by holmium laser. Routine postoperative indwelling of nephrostomy tubes were used in all cases. Result:All surgeries were successful without conversion to open surgery. The average operation time was 70 (50-90) min. The intraoperative blood loss was 20-100 ml. Urethral catheter, nephrostomy tube and double-J tube were pulled out two days, five to seven days and two months after the operation respectively. The nephrostomy incision heals itself 24 hours later without urinary fistula. The average hospital stay was 8 (range, 7-9) d. After 3-24 months of follow-up period, 29 cases have no recurrence except one patient had recurrence with the cyst diameter less than 2.0 cm. Conclusion: Minimally invasive percutaneous nephroscopy by holmium laser for endo-incision and drainage of deep kidney cysts is a new procedure with less invasion, safe and efficiency compared with other sugeries.Key words minimally invasive percutaneous nephroscopy; holmium laser; endo-incision and drainage; renal cyst