Addison’s disease or primary adrenal insufficiency is a rare endocrine disorder that results from the inability of the adrenal cortex to produce enough steroid hormones, cortisol and aldosterone to meet the body’s needs. Cortisol is an important hormone with diabetogenic functions. It increases appetite and blood pressure, decreases inflammatory and immune response as well as helps the body respond to stressors. It is under the regulation of the hypothalamic-pituitary-adrenal axis. ACTH stimulates the release of cortisol while cortisol inhibits its own production. Primary adrenal insufficiency presents with muscle weakness, weight loss, hypoglycaemia, depression and irritability, irregular or absent periods, impotence, hyperpigmentation etc. This lifelong disease is managed with hormone replacement therapy and regular patient follow up.