About one third of all patients with a pheochromocytoma are carriers of germ line mutations of 1 of the 10 susceptibility genes. Thus, these patients can be diagnosed and classified with specific tumor syndromes. This group is composed of the entities of multiple endocrine neoplasia type 2 (MEN2) due to mutations in the RET gene, von Hippel-Lindau disease (VHL, VHL gene), the paraganglioma syndromes types 1-4 (PGL1-4) due to mutations of the genes SDHD, SDHAF2, SDHC, SDHB, neurofibromatosis type 1 (NF1) due to mutations of the NF1 gene and familial pheochromocytoma syndromes due to mutations of the SDHA, TMEM127 and MAX genes. Patients with hereditary pheochromocytomas run a lifelong risk of relapse of pheochromocytoma. In addition extraparaganglial tumors are frequent and include medullary thyroid carcinoma in MEN2 or renal cancer or neuroendocrine pancreatic cancer as well as hemangioblastomas of the retina and the central nervous system in VHL. Furthermore, renal cancer may be associated with PGL4 and PGL3. In conclusion, molecular genetic screening is essential for the diagnosis of pheochromocytoma-associated cancer syndromes and is thus the cornerstone for successful lifelong preventive medicine of such patients and their relatives.