Laparoscopic lymphocele drainage is considered the gold standard for the treatment of lymphoceles after kidney transplantation. We report on a female patient who developed a symptomatic posttransplant lymphocele. After laparoscopic lymphocele drainage the patient presented with acute pain in the left lower abdomen. A CT scan showed a hernia into the peritoneal window. This is a rare but potentially severe complication after intraperitoneal lymphocele drainage. CT imaging and swift reoperation with enlargement of the peritoneal window are critical to avoid serious complications. To avoid bowel incarceration, the peritoneal window should be as large as possible.