Hypoglycaemia is an uncommon manifestation of hypopituitarism in non-diabetic adults. A 47-year-old woman with Cushing's disease was treated with bilateral adrenalectomy and pituitary radiotherapy following unsuccessful trans-sphenoidal surgery. Twenty years later, she presented with a tonic-clonic seizure and recurrent symptoms suggestive of spontaneous hypoglycaemia. Her symptoms continued despite manipulation of her glucocorticoid replacement therapy. Recurrent severe hypoglycaemia resolved after identification and treatment of her concomitant growth hormone deficiency. In patients with hypopituitarism, undiagnosed growth hormone deficiency can influence glucose metabolism and predispose to severe hypoglycaemia.