Data have been compiled from approximately 37,000 stool examinations upon military and allied personnel passing through the Naval Hospital, Bethesda, Maryland. The figures indicate a general downward trend in the incidence of most intestinal fauna since World War II, the greatest apparent reduction of protozoans occurring during period prior to 1951. Although a point of conjecture, it seems possible that the marked reduction in protozoans, including E. histolytica, may be due to the extensive use of antibiotics in recent years. For most years hookworm is recorded more frequently than Ascaris. Enterobius occurs very infrequently considering the fact that children were included each year. During the 11 year period Diphyllobothrium latum, Taenia solium, Clonorchis sinensis, Schistosoma japonicum and S. mansoni are represented by single cases of infection.