Schmidt's syndrome combines several autoimmune diseases, including Addison's disease, thyroiditis and peripheral gonadal insufficiency. A 21-year-old female presented 15 days prior to admission with a digestive complaint of nausea, vomiting, generalised asthenia and epigastric pain, all evolving in a context of weight loss. Clinical examination revealed an altered patient, hypotensive to 80/60 mmHg, normocardial to 70 bpm. Paraclinical examinations revealed acute renal failure, hyperkalaemia (8 mmol/l) and hyponatraemia (124 mmol/l). Given the hyperkalaemia without electrical signs on ECG, the patient was treated with Kayxalate and calcium gluconate and hydration with saline and sodium; the blood ionogram improved. In the face of chronic constipation, a TSH was performed, returning to 11 uui/ml with antiTPO antibodies at 1000. An ultrasound scan revealed thyroiditis, and the patient was put on levothyrox 50ug/d. The patient continued to suffer from profound asthenia and also reported secondary amenorrhoea for 4 months with negative BHCG and a hypophysiogram showing hypergonadotropic hypogonadism in favour of primary ovarian failure. On re-examining the patient, our attention was drawn to the presence of hyperpigmentation of the skin and slate- coloured patches, slate-coloured patches in the oral mucosa. The diagnosis of Addison's disease was suspected. A cortisol assay was ordered, which came back collapsed at 0.01μg/dl with ACTH elevated to 199pg/ml with anti-21-hydroxylase antibodies at 5.0U/ml (VN<0.4) confirming the diagnosis. The patient was started on intravenous hydration and hydrocortisone, with marked improvement in clinical and paraclinical parameters and restoration of menstrual cycles, followed by oral hydrocortisone and fludrocortisone. As part of the etiological diagnosis, an adrenal CT scan revealed adrenal atrophy (absence of visible adrenal parenchyma). Other autoimmune disorders in the context of polyendocrinopathy were ruled out in our patient. Adrenal insufficiency is most often caused by an autoimmune disease. Autoantibodies to steroidogenic enzymes in the adrenal cortex are present in 86% of patients with primary autoimmune adrenal insufficiency, the most common antibody being anti-21- hydroxylase.