Surgical resection of adrenal neoplasias with endocrine activity is principally indicated. In adrenal neoplasias without endocrine activity, surgical removal is indicated in relation to tumor size. Surgical access and extent of resection are the major problems related to adrenal surgery. From 1980 to 1996, in 154 patients (62 m, 92 f) primary and unilateral adrenal tumors (139 benign, 15 malign) were resected. 93 resections were performed transperitoneally, 13 extraperitoneally, and 48 retroperitoneoscopically. Subtotal adrenal resections were performed in 23 benign tumors smaller than 4 cm. Perioperative lethality was 0%, morbidity was 31.8%. Malignancy was correlated to tumor size: In 114 tumors smaller than 5 cm, no malign neoplasia was found, whereas in 40 tumors larger than 5 cm, 15 specimen were malign. Operating time of the retroperitoneoscopic method was significantly longer than of open procedures (p < 0.05). Postoperative analgotic medication was significantly reduced after endoscopic surgery compared to transperitoneal or extraperitoneal surgery (p < 0.0001). No tumor recurrences occurred after subtotal adrenal resections (mean follow up: 5.7 [1.3 years]). In patients with adrenal carcinomas, 5-year-survival was approximately 15%. In adrenal neoplasias smaller than 5 cm, malignancy is extremely rare. Therefore, less aggressive surgery with a lower morbidity (extraperitoneal approach) and reduced postoperative pain (retroperitoneoscopic approach) including function preserving resection is indicated in these lesions. Due to the high incidence of malignancy, adrenal tumors larger than 5 cm should principally be treated by conventional transperitoneal surgery.