BACKGROUND Surgery involving the right retroperitoneum can result in lymphatic (chylous) leakage from the cisterna chyli located anterior to the L1 and L2 vertebra or from lymph node dissection. This report describes a 46-year-old woman with retroperitoneal lymphatic (chylous) leak following right adrenalectomy for a nonfunctional adrenal adenoma. CASE REPORT A 46-year-old woman presented with a medical history of hypertension. An adrenal tumor (3.2×2.0 cm) was identified by computed tomography (CT). She was admitted for right retroperitoneoscopic adrenalectomy. The drainage volume of the drainage tube increased on the second day after surgery. The fluid had a milky and turbid discharge. She was started on a high-protein fat-restricted diet. In addition, 3 mg somatostatin acetate was administered daily. The chylous discharge dramatically decreased. After confirming that there was no increase in discharge, the drainage tube was removed on the 11th postoperative day. There was no recurrence of chylous fluid in 5 months. CONCLUSIONS This report shows that lymphatic (chylous) leak can be a complication of retroperitoneal surgery. The most important factor is the prevention of chylous complications. Even if no lymphatic leakage is found, it is necessary for the laparoscopic surgeon to fully coagulate the lymphatic channels. In most cases, it can be managed with conservative treatment.