Chylous ascites is caused by an accumulation of lymphatic fluid in the peritoneal cavity secondary to a rupture or obstruction of the abdominal lymphatic ducts. It has a milky appearance and is rich in triglycerides. The most frequent etiologies are neoplasms, liver cirrhosis, and ruptured lymphatic vessels after abdominal surgery. Clinically, it manifests as abdominal distention and increased abdominal girth. The presence of triglycerides in ascites fluid is the most useful diagnostic criterion. Treatment consists of a high-protein diet with fat restriction and medium-chain triglyceride supplements. Surgery is reserved for refractory cases. We present the case of a 66-year-old patient with a diagnosis of chylous ascites secondary to retroperitoneal lymphadenectomy.