Summary The patient described developed 2 separate episodes of insulin resistance and on each occassion daily administration of soluble insulin in a daily dose of 980 units failed to achieve satisfactory control. Both episodes responded to steroid therapy. The maximum binding capacity of the serum for insulin was measured on each occasion; in the first episode it was grossly elevated whereas the second time the level was unremarkable. She is currently free of diabetic complications and satisfactorily controlled on a sulphonylurea and diet.