Bovine trichomoniasis is a venereal infection that reduces the fecundity of cattle. It is caused by Trichomonas foetus, a flagellated protozoan which inhabits the genital tract, causing inflammation and partial sterility. Both sexes are susceptible to infection. In females it is usually of short duration and frequently terminates sponaneously following abortion. In males the disease has both acute and chronic stages. During the acute stage the prepucial membranes become inflamed and a muco-purulent discharge develps in which trichomonads are abundant. In the following chronic stage symptoms disappear, but the animal remains a carrier and is a dangerous source of infection to healthy cows. Diagnosis is made by examining the material from infect organs for the specific parasite. The cell body of Trichomonas foetus is fusiform or napiform. It varies from 9 to 20 microns in length, and from 3 to 7 microns in width. Its salient features are an undulating membrane and 4 flagella arising from the blepharoplast, 3 of which are anterior and free, the fourth proceeds caudad bordering the undulating membrane for its entire length and projecting unattached behind. By means of the flagella and undulating membrane the organism move jerkily through an irregular course, as is characteristic of the genus Trichomonas. Dovine trichomoniasis has a wide geographic distribution. In Europe it has been reported from Italy, France, Germany, Holland, and England. Futamura has reported it from Japan. In the United States the infection is known to be present in the states of New York, Pennsylvania, Iowa, Illinois, Maryland, Texas, Michigan, California, and Utah. Survey work done in Utah under the direction of the Utah Agricultural Experiment Station includes examination of herds in Cache, Utah, Davis, Sanpete, and Sevier Counties. Infections were found present in all counties where examinations were made except Sevier. Because of unrestricted commerce of cattle among the important live-stock centers, it is supposed that trichomoniasis is widely spread and probably exists in some cattle in the majority of the counties of the state.