The incidental finding of hypercalcaemia during multi-channel screening was the initiating event in 33 (45 per cent) of 79 consecutive cases of surgically treated primary hyperparathyroidism. This subgroup was asymptomatic as defined. Although significant biochemical differences existed between symptomatic and asymptomatic cases, a range of metabolic indices of bone turnover fell postoperatively in almost all asymptomatic subjects, although initially abnormal in only 35 per cent. Achievement of normocalcaemia was significantly surgeon-dependent.