Objective To discuss the feasibility,safety and efficacy of robot-assisted laparoscopic adrenalectomy(RALA) in the treatment of complicated adrenal tumors that unfit for conventional laparoscopic adrenalectomy.Methods Fifty-six patients with complicated adrenal tumors underwent RALA from August 2012 to March 2015.Twenty patients were male and 36 patients were female.Preoperative ultrasound and CT scan indicated that tumor of 40 patients were in the left side,and 16 in the right.Images showed that the maximum diameters of the tumors were 4.5~11.9 cm,with an average of 6.7 cm.The reasons to choose RALA were as follows: large tumors(≥5 cm) in 35 cases,patientsoverweight or obesity in 29 cases,the need or the desire to save the normal adrenal tissue in a great extent in 11 cases,tumors compressing large vessels or important organs in 13 cases,the possibility that the tumor may be a metastasis in 3 case.Twenty-two cases had 2 or more reasons described above.All surgeries were performed by lateral transperitoneal approach started with the paracolic gutter.General anesthesia was used in all cases.Four trocars (3 robotic arms and 1 assistant port) were used in the left-sided adrenalectomies and 5 trocars (3 robotic arms and 2 assistant ports) were used in the right-sided adrenalectomies.Results All the operations were successful without conversion to open surgery.The mean docking time of da Vinci surgical system was 10 min.The operative time was 30~100 min,with an average of 62 min.The estimated blood loss was 10~300 ml,with an average of 90 ml.No transfusion was needed during the surgeries.The length of postoperative hospital stay was 4.0~10.0 d,with an average of 5.7 d.Postoperative pathology showed pheochromocytoma in 12 cases (including 4 paraganglioma),macronodular adrenal hyperplasia in 4 case,adenoma with hyperplasia in 8 cases,adenoma in 16 cases,myelolipoma in 4 case,metastatic tumor in 3 case,large cyst in 5 case,calcified cyst in 4 case.No recurrence was found during the follow-up of 2 to 10 months.Conclusion For patients with adrenal tumors that unfit for conventional laparoscopic surgery,RALA may provide an alternative option for the advantage of delicate manipulation and three-dimensional magnifying image.