An appendiceal abscess is usually treated conservatively. Drainage of the abscess is instituted if this treatment is unsuccessful. Some surgeons practise immediate appendectomy and abscess drainage. An alternative ultraconservative approach whereby abscess drainage is avoided has been reviewed retrospectively. Twenty-eight patients were treated by observation only. They remained in hospital for between 1 and 36 days (median 10 days) until their signs and symptoms disappeared. No patient required surgery or developed complications in hospital. One patient developed acute appendicitis 10 days after discharge. One developed a recurrent abscess. Another group of 19 patients were treated over the same period of time by immediate operation. Ten developed postoperative complications. Hospitalization ranged from 4 to 36 days (median 8 days). Ultraconservative management of appendiceal abscess is a safe and effective alternative to immediate surgery, or ultrasound- or computed tomographic-guided drainage.