Object To evaluate the efficacy and safety of retroperitoneal laparoendoscopic single-site surgery(LESS)in the treatment for adrenal mass or renal cysts.Methods Between Feb 2012 and Mar 2012,8 consecutive patients underwent retroperitoneal LESS for adrenal masses(5cases)or renal cysts(3 cases).Patients demorgraphics and peri-operative data were documented.A 3-cm incision between 12th rib margin and illiac crest was made on midaxillary line.600~1000ml air was injected to dilate the retroperitoneal space using a home-made balloon.A homemade multichannel single-site port was inserted.The two working channels were established by an assistant maintaining the trocars within the incision.Adrenalectomy or renal cyst decortication was carried out respectively.All procedures were performed with this homemade multichannel single-site device and standard laparoscopic instruments.Results All retroperitoneal LESS procedures were successfully completed without any complications.No procedure was converted into standard laparoscopic or open surgery.The mean operative time was 105 min(range from 70 to 130 min),the mean estimated blood loss was 35ml(range from 20 to 60 ml).The mean post operation stay was 4.5 days(range from 3 to 7 days).Conclusion Retroperitoneal LESS for adrenalectomy or cysts decortications of renal cysts is feasible and safe.