A 48-year-old man, with end-stage renal disease (ESRD) on haemodialysis, presented to the emergency department with sulphonylurea-induced hypoglycaemia. His hypoglycaemia was persistent despite glucose infusion, so he was treated with octreotide. Octreotide administration reversed the hypoglycaemia but also resulted in severe hyperkalaemia. The patient was urgently dialysed, the octreotide was discontinued and his potassium normalized. We believe that the hyperkalaemia was caused by octreotide-induced insulin suppression and resultant impaired cellular potassium uptake. Although octreotide may be an effective therapy in refractory sulphonylurea-induced hypoglycaemia, it should be used with caution in patients on dialysis.