The normal adrenal glands can be detected by high-resolution-sonography in a high percentage of cases. Sonography is also highly sensitive in the diagnosis of tumours of the adrenal glands. Only some of those tumours are hormonally active. Amongst the benign tumours, adenomas are the most frequent (up to 8%). Pheochromocytomas are less frequent (4.8% in uFNB statistics). Amongst the malignant tumours, metastases are more frequent than primary carcinomas (32.5% vs. 19.8% in uFNB-statistics). The adrenal glands are the fourth most common location of metastases. Bronchiogenic carcinomas, malignant melanomas, carcinomas of the breast and stomach as well as renal carcinomas metastasize into the adrenals most often. Much less frequent are infiltrates of lymphomas in adrenal glands tumours (3.4%). Incidentalomas are accidentally detected tumours of the adrenal glands without clinical symptoms. Malignant tumours only represent a very small part of incidentalomas (0.2%). They seldom show hormonal activity. In the case of an accidentally detected tumour, we propose a minimal laboratory profile (24-h-urinary-catecholamines, dexamethasone-test, electrolyte metabolism). The uFNB of the adrenal glands has a high sensitivity (90-95%). Complications are rare (pneumothorax, bleeding, pain; approximately 3%). Biopsy of pheochromocytomas (2-4% malignant) is dangerous because of the risk of provoking a hypertensive crisis. Case studies have been published about this problem. On the other hand, numerous cases of uncomplicated biopsies have also been published. Considering the excellent imaging methods and laparoscopic surgery methods on hand, the indication of FNP is restricted to the following cases: 1. the presence of a metastasis leading to therapeutical consequences; 2. suspected lymphoma 3. undefined lesion (3-5 cm), hormonally inactive, without typical signs of a tumour 4. patients refusing surgery. 5. uFNB in case of tumours of undefined dignity is only justified in specific cases. Recommendations for this procedure in accidentally detected tumours of the adrenal glands: < 3 cm and hormonally inactive --> US-follow up, > 5 cm + suspected tumour --> surgery, 3-5 cm uFNB after laboratory diagnostics.