This study is a clinical review of 154 patients with fistula-in-ano, which were treated at the Department of General Surgery of Ewha Womans University Hospital from January, 1993 to December, 1996. The male to female ratio was 4:1, and the prevalent of groups were in the 3rd and 4th decade. The symptoms were anal discharge in 123 cases(79.8%), pain in 21 cases (13.6%), palpable mass in 9 cases(5.8%). 53.8% of the patients showed a duration of symtoms which were within 6 mouths. The previous or combined anal diseases were anal abscess in 62.4%, postfistulectomy in 29.0%, hemorrhoid in 4.3%, and anal fissure in 1.2%. The histopathologic etiologies were chronic non-specific inflammation in 94.8%, and tuberculosis in 3.2%. 38.8% of the patients showed an external openings in the anterior midline, 25.9% in the posterior midline, 13.0% in the left lateral, and 10.4% in the right lateral portion of the anus. In 84.4% of the patients, the interval opening was identified. The intersphincteric type was the most common. The operative procedures included fistulotomy with lay open in 129 cases(83.8%), fistulotomy with seton in 16 cases(10.4%), and fistulectomy in 8 cases(5.2%). The days of hospital stay were mostly within 14 days. The main postoperative complications were urinary retention and reccurance, which were identified in 4.6% each of the patients. The acuracy and the predictive value of fistulography, a method of identification of the internal openings showed an accuracy of 73%, the predictive value of positive tests was 95% and that of the negative test was 30%.