Protein-losing enteropathy (PLE) is defined as a condition in which excess protein loss into the gastrointestinal lumen, due to various causes, is severe enough to produce hypoproteinemia and hypoalbuminemia. We report a 28-year-old Japanese woman with PLE. She had been diagnosed with AIDS and disseminated Mycobacterium avium complex (MAC) infection at age 26. Although highly active antiretroviral and antimycobacterial treatments helped her overcome this critical situation, 2 years after initiation of the treatments, she was readmitted to our hospital because of hypoalbuminemia and edema of the lower extremities, and she was diagnosed, by the use of double-balloon enteroscopy, with PLE due to intestinal lymphangiectasia (IL). The etiology was thought to be obstruction of the mesenteric and retroperitoneal lymphatic drainage systems by MAC lymphadenitis. Even with intensive antimycobacterial treatment, octreotide treatment as a long-acting somatostatin analogue, and a low-fat diet enriched with medium-chain triglyceride, IL was not cured during the follow-up period. In patients with AIDS, complete clinical remission of MAC (especially disseminated MAC) infection is very difficult.