A patient with disseminated gastrointestinal sarcoidosis and non-Hodgkin's malignant lymphoma developed diarrhea and polyadenopathy. Laboratory analysis revealed the presence of protein-losing enteropathy without biological signs of malabsorption. Gastrointestinal biopsy specimens showed numerous sarcoidosis nodules without neoplastic proliferation in the stomach, small intestine, and rectum. The patient's course was favorable after treatment with prednisone and chlorambucil. Disseminated gastrointestinal sarcoidosis may be a previously unidentified cause of protein-losing enteropathy.