Purpose To clarify the characteristics of surgical approaches to laparoscopic adrenalectomy we performed background matched analysis of clinical outcomes of the 3 approaches. Materials and Methods From February 1992 to July 2000 we performed 118 laparoscopic adrenalectomies in 115 patients with adrenal tumors. For these operations we used the anterior transperitoneal approach in 46 patients, the lateral transperitoneal approach in 32 and the lateral retroperitoneal approach in 40. Results To exclude the learning curve effect we eliminated our initial 20 patients treated with the anterior transperitoneal approach. To allow background matching of the 3 groups we also excluded 14 patients with tumors more than 5 cm., 6 who underwent conversion to open surgery and 1 patient who required 5 days of bed rest for retroperitoneal hematoma caused by bleeding from a trocar port. The final analysis included 16, 25 and 36 cases managed via the anterior transperitoneal, lateral transperitoneal and lateral retroperitoneal approach, respectively. Average operative time was significantly shorter for the lateral transperitoneal approach. Postoperative recovery was not significantly different in the lateral transperitoneal and lateral retroperitoneal groups. Postoperative complications included mild paralytic ileus in 2 patients and shoulder tip pain, probably peritoneal irritation due to carbon dioxide insufflation and bowel preparation, in 4 in the transperitoneal groups. Our results imply that the easiest procedure is the lateral transperitoneal approach but the lateral retroperitoneal approach is slightly less invasive. Conclusions Although it is important to remember that this study was not a prospective randomized trial and, thus, had from certain biases, we believe that if a tumor is more than 5 cm. and/or the surgeon is not yet skilled in laparoscopic adrenalectomy, the lateral transperitoneal approach is the most suitable method. If the surgeon has performed at least 20 operations, the adrenal tumor is unilateral and the lesion is less than 5 cm., the lateral retroperitoneal approach seems to be more suitable because of its minimally invasive nature. The lateral retroperitoneal approach is also preferred in patients with a history of upper abdominal surgery. With improvements in technique and new instruments the time required for the lateral retroperitoneal approach has been significantly decreased.