99Tcm-HEDP bone scans were obtained in 20 acromegalic patients. Twelve patients had active disease with elevated basal serum human growth hormone (HGH) levels. Eight patients were in clinical and biochemical remission. The bone scans, assessed independently by three observers, showed features characteristic of metabolic bone disease in patients with active acromegaly. The metabolic index derived from the scan correlated well with serum HGH levels (R = 0.71, p < 0.002). The bone scan may accurately reflect oversecretion of HGH and is of potential value in the assessment of patients with acromegaly.