Post-operative chyloretroperitoneum is a rare complication in urological surgery. We experienced two cases of post-operative chyloretroperitoneum following retroperitoneoscopic left nephroureterectomy. Both cases were treated successfully with drainage, low fat diet, total parenteral nutrition (case 1 only), sclerotherapy and somatostatin analog. Laparoscopic procedures are supposed to have a higher risk of chylous complications, as CO2 pressure appears to make the operator overlook suppressing the lymphatic leakage from the resected lymphatic channels.