The vascular injuries that occur with lumbar discectomy are serious and often fatal complications. The incidence of such injuries is very low, but they are probably underestimated due to the various clinical manifestations such as retroperitoneal hemorrhage, hematoma and iliac artery-IVC vein fistula. A delayed diagnosis, and especially in case of iliac-IVC fistula, results in high output heart failure and cardiopulmonary insufficiency. We report here on 2 cases of iliac arteriovenous fistula that occurred after lumbar discectomy. An 18-year-old man and a 37-year-old man were admitted to our department with the symptoms of high output heart failure 3 and 24 days, respectively, after lumbar discectomy was performed. Both of them presented with clinical manifestations of pulmonary edema, tachycardia, hydrothorax and high output heart failure. One man died after an iliac artery stent graft and one man was salvaged after left common iliac vein ligation, aorto-common iliac artery bypass and left common iliac vein-IVC bypass surgery. Prompt diagnosis and aggressive treatment can hep to salvage the patients from these fatal complications. A high index of suspicion for this malady, based on the clinical signs, is mandatory.