Isolated cases of cervical cranial glomus tumors have been reported in association with pheochromocytoma. Two family pedigrees are presented and four individual cases discussed indicating a hereditary syndrome of pheochromocytoma associated with multiple glomus tumors of the head and neck. The hereditary potential has not previously been described. In three of the patients, the pheochromocytomas were asymptomatic at the time of initial presentation. These pheochromocytomas were discovered by arteriography after one of the patients developed a hypertensive crisis with the induction of anesthesia. The silent presence of pheochromocytomas in patients with multiple glomus tumors should be considered in the evaluation of these patients.