Of 100 uteri of ewes collected from a slaughterhouse, 44 had endometritis. These cases were classified as acute endometritis (18%), acute lymphocytic endometritis (59%), chronic non-suppurative endometritis (16%) and suppurative endometritis (6.8%). Aerobic bacteria were isolated from 26 uteri. The most commonly isolated bacteria were Escherichia coli, Corynebacterium pyogenes, and Staphylococcus aureus. These organisms then were inoculated into the uteri of normal ewes. None of the inoculated bacteria consistently produced any particular type of endometrial lesion.