Tumors of the adrenal gland are not uncommon. Patients with these tumors usually demonstrate symptoms associated with the biochemical substance or hormone produced by the tumor. Tumors of the adrenal cortex, whether benign or malignant, are often associated with excess production of steroids, whereas tumors of the medulla are generally associated with overproduction of catecholamines. With the ubiquitous use of computed tomographic imaging, many asymptomatic adrenal lesions are discovered, presenting a management problem for the clinician. The algorithm for investigating so-called adrenal “incidentalomas” in the current era of cost containment continues to evolve. This review addresses current trends in the clinical evaluation, biochemical testing, and nuclear and radiologic imaging in the diagnostic work-up of these neoplasms. The mainstay of treatment is still surgical extirpation, the only curative modality. However, advances have occurred in adjuvant therapies, perhaps best typified by the neoadjuvant use of131I-methyl iodobenzylguanidine in the treatment of neuroblastoma.