Three patients, 2 women and 1 man, with primary (AL) amyloidosis without congestive heart failure are described; all 3 patients presented reduced I-123 metaiodobenzylguanidine (MIBG) myocardial uptake suggesting marked cardiac sympathetic denervation. This is the first time myocardial adrenergic denervation is described in patients with AL amyloidosis without evidence of congestive heart failure; the observed denervation could be implicated in the pathogenesis of cardiac conduction disturbances which are common in this disease.