The causal relationship between dyslipidaemia and insulin resistance, two central components of the metabolic syndrome, is still poorly understood. We describe a 76-year-old patient with Type 2 diabetes mellitus and pronounced hypertriglyceridaemia. The patient required a total insulin dose of 148 IU/day for decent glycaemic control. The addition of the fibrate gemfibrozil to her medication resulted in a remarkable reduction in triglyceride levels (from 31.7 to 7.1 mmol/l). Consequently, the patient experienced recurrent hypoglycaemic episodes concurrent with a massive reduction in insulin requirements. Eventually, the insulin dosage was reduced by more than 65% to 48 IU/day, and HbA1c levels dropped from 9% to 6.5% over a period of 5 months without alterations in lifestyle, diet, body weight, or any other blood chemical values. Thus, this case report illustrates that treatment of hypertriglyceridaemia can reduce insulin requirements and harbours the risk of hypoglycaemia in patients with insulin-treated Type 2 diabetes mellitus.