Carotid body tumours, or chemodectomas, can occur on both sides of the neck (5%), and this bilaterality increases sixfold (30%) where a familial pattern is evident. The known pathological behaviour of chemodectomas makes early recognition and management desirable, especially when an inherited predisposition can be anticipated. Difficulties in clinical diagnosis and the hazards of blind exploration have imposed a reliance on contrast angiography, which is a potentially dangerous procedure. The family tree of a patient with bilateral chemodectomas was traced and 28 individuals were studied using radionuclide angiography (99mTechnetium gluconate), a quick, safe technique with a high yield. Bilateral chemodectomas were observed in five siblings, establishing conclusively the existence of a dominant hereditary trait. Excision of newly discovered tumours was accomplished without complication. The techniques which permitted such a favourable surgical outcome are discussed, emphasising the view that these tumours are best dealt with by vascular surgeons.