In this study, we evaluated the efficacy of long-term seton drainage in the management of 13 patients with severe perianal Crohn's fistulas which had proven to be intractable to conventional therapy. After adequate curettage of the fistulous tracts and infected tissue, either a Penrose drain or a fine polyethylene catheter was inserted to encircle the tracts and tied. Patients were followed up for a mean period of 12.1 months. Perianal pain disappeared or improved in all 13 patients, while the body temperature of all 7 with pyrexia dropped to within the normal range. Discharge disappeared or diminished in 77% (10/13) and tenderness disappeared or improved in 77% (10/13). Induration disappeared or improved in 69% (9/13). Overall, good results were achieved in 10 patients, although 3 required redrainage. In one of these patients, a good result was achieved after colostomy was performed for active intestinal disease. Nevertheless, 2 patients did not improve, one of whom required lay-open surgery after seton treatment. In 8 of the 13 patients, some seton drains were able to be removed, and none of the patients experienced any soiling or leakage. Thus, we conclude that seton treatment is worthwhile in the management of perianal Crohn's fistulas as it alleviates the symptoms and simplifies multiple tracts. Moreover, it preserves sphincter function, is less invasive, and can be managed easily.