Ascites is a rare complication of renal transplantation. Ascites has been reported after kidney transplantation due to rejection, decapsulation of the graft, urinary or vascular leak, lymphocele, transudation, or infection. While technical complications of the procedure are the most frequent cause, portal hypertension and graft rejection are other causes. Ascites can occur after renal transplantation independent of kidney function. Usually, a time relation can be made between the surgical procedure and ascites development. Chylous ascites is still more uncommon; it is usually related to traumatic lymphatic injury. Drugs are rarely associated with the genesis of ascites. Sirolimus has been associated with a high rate of lymphoceles, lymphedema, and pulmonary alveolar proteinosis. The exact mechanisms remain unknown. The risk for lymphocele formation with sirolimus is 12% to 15%. Ascites is an adverse effect with an incidence between 3% and 20%, but no relation between sirolimus and chylous ascites was previously established. We present a clinical report of chylous ascites in a renal transplant patient under sirolimus therapy; our investigation pointed to sirolimus as the cause.