Unlike tumors found elsewhere in the body, cancers of the endocrine organs can cause symptoms of hormonal excess in addition to mass effect, obstruction, or pain from the mass itself. Therefore physicians who care for patients with endocrine cancers must combat both the physiologic manifestations and the neoplasia. Any of the endocrine tumors can be part of a multitude of familial syndromes, so the clinician caring for these patients must always keep this possibility in mind. This chapter covers selected endocrine cancers and highlights some of the unique challenges in treating such tumors. Many common themes emerge. Diagnosis typically involves biochemical confirmation of the endocrinopathy followed by imaging to locate the tumor(s). Surgery plays a role in the initial treatment and often for recurrence and palliation. Traditional chemotherapy is of limited use for endocrine cancers, but newer, targeted therapies show more promise. This chapter covers thyroid cancer, including medullary thyroid cancer (MTC), adrenocortical carcinoma, malignant pheochromocytom (PCC), multiple endocrine neoplasia (MEN) syndromes, carcinoid tumors, pancreatic neuroendocrine tumors (pNETs), and parathyroid carcinoma.