Morbidity and mortality are higher in diabetics undergoing surgery, which most often reflect various cardiovascular complications. Ketoacidosis is the most serious acute metabolic complications of diabetes perioperatively. Ketoacidosis has adverse effects such as decreased myocardial contractility and peripheral vascular tone, dehydration and electrolyte imbalances. We encountered a case of a 47 year-old man who presented with ketoacidosis and severe hypotension 15 minutes after being administered epidural anesthesia for femoro-popliteal arterial bypass surgery. This case highlights the need for anesthesiologists to consider the possibility that ketoacidosis can mimic severe hypotension due to epidural anesthesia or cardiogenic shock.