Pheochromocytomas are rare neuroendocrine tumours with a highly variable and heterogeneous clinical manifestation. With a noticeable progress in genetics, biochemical diagnosis and tumour imaging techniques, modifications of the traditional "rule of tens" for pheochromocytomas are inevitable consequence. Diagnosis of pheochromocytoma depends on biochemical evidence of catecholamine production by the tumor. Plasma free metanephrines provide the best test for excluding or confirming pheochromocytoma and should be used as an initial screening tool, but if it is not available, urinary fractionated metanephrines could be used as an alternative method. Different anatomical and functional imaging modalities are used to localize biochemically proven pheochromocytomas. These include computed tomography, magnetic resonance imaging, single-photon emission computed tomography (SPECT) using 123/131I-metaiodobenzylguanidine (MIBG) or 111In-DTPA-pentetreotide and positron emission tomography (PET). Timely laparoscopic tumour removal in combination with appropriate pre-and intraoperative management of the effects of secreted catecholamines are essential components for excellent prognosis. (Korean J Med 2012;82:403-410)