Eubacterium suis was isolated from the bladders of 3 of 64 sows (4.7%) examined at slaughter. Two of the sows had cystitis similar to other descriptions of E suis infections in sows. There was no histologic evidence of cystitis in the third sow from which E suis was recovered. In all 3 instances, a mixed infection was present. Other bacteria present were predominantly gram-positive organisms. Eubacterium suis cystitis may be more prevalent than previously suspected. The special culture conditions required to grow this organism may account for the paucity of reports in the United States.