In order to know the prevalence rate of adrenal insufficiency among patients with renal failure due to amyloidosis; we have performed a stimulation test with synthetic corticotropin hormone (Nuvacthen test) in nine patients diagnosed of renal amyloidosis and in five controls. We also measured ACTH and plasma cortisol levels. In two out of nine patients (22%) a low ACTH, low plasmatic cortisol and an abnormal response to Nuvacthen test were detected being diagnosed of primary adrenal insufficiency. We conclude that adrenal insufficiency is not an infrequent finding in systemic amyloidosis and may be due to secondary amyloidotic infiltration of adrenal or pituitary glands. Though Nuvacthen test is a useful test to diagnose subclinical adrenal insufficiency, in our series patients with an abnormal response also had low levels of basal cortisol and ACTH and no one patient with normal basal levels had an abnormal response to the stimulation test.