Adrenalectomy is ideally suited to minimally invasive surgery based on the characteristics of adrenal tumours, which are usually small and benign. The aim of this study was to verify that laparoscopic adrenalectomy is minimally invasive and to assess the indication of laparoscopic adrenalectomy for incidentaloma. From October 1995 through August 2002, 133 patients underwent adrenal surgery at the Department of Surgery II, Nagoya University School of Medicine. Of these, 111 underwent laparoscopic adrenalectomy. All laparoscopic adrenalectomies were performed using the transabdominal lateral approach. In 50 of 133 patients, the adrenal tumours were incidentally discovered. There were 27 non-functioning adrenal tumours and six of seven preclinical Cushing's test syndrome cases incidentally discovered. Six of 27 non-functioning adrenal tumour patients underwent open adrenalectomy because of large tumour size or malignancy. Based on the present criteria for laparoscopic adrenalectomy, 15 of 133 patients were retrospectively considered to have required open adrenalectomy. The average size of a non-functioning adrenal tumour was 5.8 cm in diameter, which was equal to the average size of a phaeochromocytoma. A simultaneous bilateral laparoscopic adrenalectomy was performed in a patient in poor condition with advanced Cushing's syndrome due to adrenocorticotrophic hormone-independent macronodular adrenocortical hyperplasia (AIMAH). The adrenal glands were successfully removed without fragmentation in this patient, and the postoperative course was uneventful, thanks to the minimally invasive surgery. The laparoscopic technique assures less morbidity and faster recovery, and appears to be equally effective in eradicating functioning and non-functioning adrenal masses. The benefits of the laparoscopic approach to adrenalectomy should not result in a more aggressive attitude toward the excision of clinically silent, benign-appearing adrenal incidentalomas.