On the basis of a personal case in which two successive diagnoses of sarcoidosis and Whipple's disease were made at an interval of four years, the authors discuss the possible association or relationship between these two disorders, both diffuse, affecting the reticulo-histiocytic system and diagnosed on a histological basis. Review in the literature of 54 cases of Whipple's disease with pleuro-pulmonary lesions makes it possible on the one hand to associate with the latter numerous examples of extra-intestinal involvement, the histological appearance of which of a non-specific epithelioid granuloma does not indicate the diagnosis during the long pre-intestinal phase, and on the other hand to explain that during this period, the presence of pleuro-pulmonary lesions leads to an initial diagnosis of the probability of sarcoidosis. The practical consequences are as follows: The appearance of intestinal signs during "sarcoidosis" should lead to intestinal or mesenteric node biopsy to seek the macrophages with highly PAS positive cytoplasm characteristic of Whipple's disease. Their discovery necessitats long term antibiotic therapy which has recently transformed the outlook in this disease, invariably fatal in the past.