Perianal complications of Crohn's disease are fairly common in the adult and pediatric populations. Transrectal ultrasonography is effective for the diagnosis and follow-up of patients with anorectal abscesses and fistulas in Crohn's disease. Metronidazole and 6-mercaptopurine therapy have been used effectively to treat perianal complications of Crohn's disease in the pediatric population. Asymptomatic perianal fistulas in a patient with Crohn's disease do not require treatment. If a fistula is symptomatic and involves only a small portion of the sphincter mechanism, conventional fistulotomy may be performed with good results. Complex fistulas that involve larger areas of the sphincter are best treated by optimizing medical management and seton placement. The management of rectovaginal fistulas in the presence of Crohn's disease is controversial. Conventional fistulotomy and transvaginal mucosal advancement flap with diverting ileostomy have been advocated as primary treatment modalities. Rectovaginal fistulas secondary to ulcerative colitis may be treated by ileoanal pouch anastomosis and primary repair.