Appendicitis, usually a benign disease, can have its prognosis worsened in case of postoperative fistula. The latter occurs rarely after open appendectomy (0.133%), but accounts for 10% of the morbidity rate. The authors reviewed 22 cases of these fistulas, treated during a 24-year period (January 1970 to December 1993). The aim of these retrospective study was to precise their clinical features, to evaluate paraclinical examinations in diagnosing these complications and to give guidelines for their treatment. Fistulas occurred at day 14 in the postoperative course. In 21 case, appendicitis was severe (suppurative, gangrenous or perforated) or appendectomy quoted as technically difficult. Location of the appendix was atypical in 7 cases. Drainage of the site was performed in 17 cases at the time of appendectomy. Diagnosis was made on the aspect of the drainage fluid in 14 cases. Diagnosis workup of the fistula associated plain abdominal radiograph and abdominal ultrasonography (n = 22). Fistulography (n = 6) confirmed the clinical diagnosis of fistula, showing the leaking in all cases. Medical treatment was attempted first in 14 cases and was successful in 11 cases with a healing time from 13 to 72 days. Surgical treatment (open drainage of the site) was attempted first in 11 cases, and was mandatory in 3 other cases because of medical treatment failure: one patient died and 5 patients underwent re-operation (right colectomy in 3 cases, bypass in 1 case and re-drainage in 1 case). Fistulography in our experience, is highly reliable and is considered to be a great assistance in management of these fistulas. Medical treatment remains the best initial treatment modality. Surgery must be contemplated in case of established external fistulas, and of purulent or faecal fistulas. Nevertheless, prognosis remains poor (50% re-operation rate).