A prospective study of 100 recurrent anorectal abscesses in 97 patients was carried out to elucidate the cause of recurrence. Sixty-four patients had had one, 12 had had two, and the rest had had more than two prior abscesses. In 32 patients, the previous diagnosis was erroneous; the patients had hidradenitis suppurativa which was excised. In 68 patients, the cause of recurrence was insufficient prior treatment. Thirty-one patients (45 per cent) had fistulous abscesses requiring fistulotomy. Twenty-two patients (32 per cent) had large abscesses associated with fistula necessitating unroofing of the abscess along with fistulotomy. In 15 patients (22 per cent), no associated fistula was detected, but they were found to have missed components (i.e., ischiorectal, supralevator, postanal abscesses) and were successfully treated with drainage of the missed abscess component. All recurrent abscesses must be examined carefully under anesthesia to identify associated fistulas or missed components, or to exclude hidradenitis suppurativa.