A 65-year-old man underwent a laparoscopic nephroureterectomy with a radical retroperitoneal lymphadenectomy for transitional cell carcinoma in the pyelon of the left kidney associated with a paraaortal lymphadenopathy. Four weeks later the patient presented with weight loss, a distended abdomen and a swelling of the left hemiscrotum. With increasing complaints and the suspicion of a large lymphocele an exploratory laparoscopy with the possibility of a fenestration was performed. Intraoperatively the laparoscopy revealed a chylous ascites but failed to detect an injury to the lymph system and a localised leak. The ascites eventually resolved under a strict dietary regimen with a medium-chain triglyceride-based diet and repeated long-term drainage. We report this case to encourage a multimodal approach in this potentially fatal complication.