Neurofibromatosis 1 (NF1) and Neurofibromatosis 2 (NF2) are tumor suppressor disorders in which affected individuals are predisposed to develop benign and malignant tumors. This chapter discusses the clinical and genetic features of NF1 and NF2, and evaluates the current diagnosis and management of these conditions. Ideally, patients with NF1 and NF2 should be managed by a multidisciplinary team with input from neurology, genetics, neurosurgery, plastic surgery, sarcoma, orthopedics, ophthalmology, and otolaryngology specialists. Uncomplicated NF1 can be monitored in the local community by an experienced clinician with expertise in the disorder. Many authors have considered von Hippel-Lindau (VHL) disease in the same category as the neurofibromatoses and tuberous sclerosis. The diagnosis and clinical care of patients with VHL have been enhanced by the identification of the VHL gene, and functional studies of the VHL gene product have provided an insight into the role of hypoxia response pathways in tumor formation.