The author revises the main clinical aspect of the disease as well as its dignosis and its treatment. Rhinosporidium seeberi, first described by J.R. Seeber in 1900, then exhaustively investigated by J.H. Ashworth in 1923, has been accepted up to now as a phycomycete. Inside of the sporangial bodies, part of the polyp characteristic of the disease, are found spores, and in the spores, spherules, considered by Ashworth as food material. In 1955 the author did challenge the view of Ashworth because he had been able with the Feulgen stain to demonstrate the presence of DNA attached to the spherules. The results obtained by Vanbreuseghem were confirmed in 1964 by W.A.E Karunaratne and R. Cameron and Dorothy Russel. They were later confirmed in India by Lakshmanan. In an effort to understand better the real nature of Rhinosporidium seeberi which so far has never been successfully cultivated or inoculated in any animal, a study with the ultramicroscope has been done. Although it is difficult from the results obtained so far to decide of the real nature of R. seeberi, no proof has been found to confirm the theory of Ashworth. Quite evidently much has to be done to decide of the real nature of this interesting parasite.