Eighty-seven dogs that had perianal fistulas diagnosed at the Veterinary Medical Teaching Hospital, University of California, Davis, were treated by excision of the diseased tissues and bilateral anal sacculectomy. Males were affected more often than females (66 to 21), and the German Shepherd Dog was the predominant breed (59 of 87). Information from owners regarding long-term postoperative progress was available for 41 dogs. Twenty-two of the 41 dogs had been euthanatized, 15 (36.6%) because of complications related to perianal fistulas and 7 because of unrelated causes. The mean postoperative period, ie, from the time of surgery to the time of euthanasia, was 34.7 months (range, 1 to 82 months). The remaining 19 dogs were examined after a mean postoperative period of 42.3 months (range, 13 to 100 months). Postoperative complications included development of clinically evident fistulas in 23 of the 41 dogs (56.1%), lack of normal continence (26.8%), tenesmus (19.5%), flatulence (17.1%), and anal stricture (14.6%). Twenty-one of the 41 dogs (51.2%) were judged by their owners to be satisfactory pets or to have been satisfactory pets before euthanasia for unrelated reasons