A 52-year-old-woman with non-insulin-dependent diabetes mellitus developed carcinoma of the pancreas and had a Whipple's resection performed. She required pancreatic exocrine supplements and insulin post-operatively. Five years later metastatic disease became apparent, and was accompanied by episodic spontaneous hypoglycaemia necessitating the cessation of insulin therapy. Hormonal analysis was performed, off insulin, at a time of hypoglycaemia (glucose 0.9 mmol l-1) and showed negligible insulin concentrations (< 2 mU l-1) but raised IGF-II together with low IGF-I concentrations (1.85 and 0.1 U ml-1, respectively). The association between diabetes and pancreatic carcinoma, and the pathogenesis of non-islet cell tumour induced hypoglycaemia (NICTH) are discussed.