The Authors study 270 cases of Schistosomiasis mansonica observed in the Hospital Santa Maria Bertila, Guiratinga, East Mato Grosso. AH but 3 came from the endemic areas of the States of Minas Gerais, Pernambuco, Bahia, etc. Three were indigenous of Mato Grosso. According to the Authors the presence of autochtonous cases of Schistosomiasis mansonica in Mato Grosso is of greast epedemiological significance.