[What is your diagnosis? (author's transl)].

The clinical and radiographic findings, surgical treatment and post-operative course in a dog with a recurrent fistula in the neck are reported. Although a foreign body was discernible on a survey radiograph, pre-operative contrast radiography was carried out using a watersoluble contrast medium, the advantages of which are discussed. The foreign body, a piece of treebark, was removed at surgery. The fistula did not recur during a post-operative period of ten months.