OBJECTIVE--To establish guidelines for the management of a pregnancy that is complicated by acute appendicitis. DESIGN--Retrospective study. SETTING--University Hospital, Copenhagen, Denmark. SUBJECTS--16 patients operated on for symptoms of acute appendicitis during the 15 year period 1974-1988. RESULTS--In 12 patients (75%) the diagnosis was confirmed histologically. The signs and symptoms were classic, and three patients had contractions. One fetus died, in a patient with appendicitis complicated by intraperitoneal abscess. In all uncomplicated cases the pregnancy proceeded to term and the deliveries were normal. CONCLUSIONS--Pregnancy should not deter a surgeon from removing an appendix, once the diagnosis is suspected; no pregnancy was affected by removal of a normal appendix. We recommend that prophylactic antibiotics and tocolytic drugs be given in all cases. Simultaneous caesarean section should be done only if there are obstetric indications.