Acute adrenal crisis is a life-threatening disorder. Cardiovascular complications of the condition are usually limited to hypovolaemic hypotension and shock. An acute reversible cardiomyopathy and heart failure in association with acute adrenal crisis is rarely reported, particularly in children. A 6-year-old girl with adrenal crisis which was complicated by acute reversible cardiomyopathy is reported. Inotropic and ventilatory support in addition to intravenous hydrocortisone and furosemide therapy were required to achieve cardiovascular stability. The cardiomyopathy resolved over 5 days and she was discharged with normal cardiac and intellectual functions. Cardiomyopathy should be considered in patients with acute adrenal crisis demonstrating any symptoms or signs of heart failure.