Adrenal insufficiency (AI) requires a prompt diagnosis to avoid associated mortality. New etiologies have been added to the classic causes. Aim: To establish the frequency of different causes of AI and to describe, the characteristics of patients treated at a university center. Methodology: Retrospective review of clinical records, laboratory tests and images of patients diagnosed with AI over a 11-year period. The cases were divided according to diagnosis into primary (PAI) or secondary (SAI). Results: Of 102 patients (51 females (F), 40 (39%) had PAI, (15M/25F) and 62 (61%) SAI (36M/26F). Evolution of disease: 4.6 +/- 9.5 (0-38) and 5.5 +/- 7.7 (0-32) years in PAI and SAI respectively. Age at diagnosis: 43.6 +/- 16 years in PAI and 46.6 +/- 18.6 years in SAI. The most frequent etiologies were: Addison's disease (AD) (65%) in PAI and macroadenomas in SAI (64.5%). HIV infection was associated with one case of PAI and one case of SAI. Two cases of SAI were secondary to pembrolizumab-induced hypophysitis. Symptoms such as asthenia, weight loss, abdominal pain and muscle fatigue were significantly more frequent in PAI. Five percent of cases with SAI did not show symptoms of hypocortisolism. Fifty eight percent of patients with AD (15/26) had associated autoimmune thyroid disorders. We observed a trend to hyponatremia, hypercalcemia and in PAI, although to hyperkalemia and increased ACTH and plasma renin activity. Conclusion: The clinical picture in AI is nonspecific but asthenia, associated with other symptoms and signs characteristics, together with laboratory findings, may guide the diagnosis, as well as the presence of endocrinopathies or autoimmune diseases. The high prevalence of HIV infection and the increasingly use of check point inhibitors make it necessary to implement AI screening protocols in these groups.